We saw the Earth destroyed and in a heartbeat, everything and everyone we knew was gone. There were five of us: the crew of the space shuttle Odyssey, and we were the only survivors. A mysterious being who called himself The Seeker rescued us and sent us back in time. And now we have five years to live over. Five years to discover who or what destroyed the Earth. Five years to stop it from happening... again.

While on a routine shuttle mission, the crew of the space shuttle Odyssey witness the destruction of the Earth. They are rescued by a mysterious alien who calls himself The Seeker. The Seeker has travelled for hundreds of years and found over 50 planets destroyed, including his own. The Odyssey crew are the first survivors of a shattered world he has ever found, and he jumps at the chance to try and prevent the Earth's destruction. The Seeker projects the five's current brain patterns back five years, and implants them in their younger bodies. With little to go on other than "seek within your own", the five struggle to discover who destroyed the Earth, how, and how they might be able to prevent it. They begin gathering pieces of the puzzle, which reveal a race of sentient artificial lifeforms, their synthetic avatars, and a government conspiracy. Unclear who the good guys are and who the bad guys are, they begin affecting the timeline, changing it in ways they couldn't anticipate, and become an integral part of the fate of the planet. Along the way, they must also deal with personal challenges and tragedies without losing sight of their ultimate goal: to save the world.

	Chuck Taggart (Peter Weller) is one of NASA's finest "old school" commanders. A former combat pilot, he comes from an Air Force family, following in the footsteps of his late father. Although his relationship with his own father was strained, his relationship with his two sons is equally fraught with tension at times and Chuck seems unaware that he is repeating the same mistakes with Neil that his own father made with him. Chuck can be a bull-headed sonofabitch, emotionally distant, and difficult to deal with. However, he is also intelligent, intuitive, plain-speaking, and commands the loyalty of those around him with ease. Chuck has a very close relationship with his wife, Paige, whom he sees as an equal partner in the adventure of his life. He attempts to explain what happened to him and Neil in the future several times, only to be met with anger and confusion from the woman he met and married over 25 years earlier. When Paige is killed by a sentient "skin", Chuck is shattered, and briefly leaves the group and his son.
	Genius-smart and driven, Neil (Christopher Gorham) nonetheless has a chip on his shoulder when it comes to his relationship with his parents— particular his father Chuck—who had largely ignored him in favour of his "golden child" elder brother Marc. Eager to prove himself, Neil went from a metal-head stoner in high school to NASA's youngest astronaut at age 22. Regardless of his amazing achievements, he still feels as if he's living in Marc's shadow, despite the fact that in the original timeline, Marc went AWOL because he was washing out of the astronaut programme. Finding himself back in his junior year of high school, Neil has a difficult time making the adjustment from 22-year-old wünderkind with a Porsche, a condo, and a Harley to a 17-year-old no one believes in. His relationship with his friends, particularly his girlfriend Holly, is strained. And while the rest of the team chases down leads, he's often stuck at school studying for a Trig test. While Chuck may not always understand his youngest son—or be able to relate to him—Chuck relies on Neil and is proud of him, even if he is occasionally harder on Neil than he is the other members of the team. The hardest part remains being written off by his mother, who looks at him and sees a "work in progress" and when being told of his "future" achievements, seems only able to express surprise. When his mother is killed and his father takes off, Neil may be feeling abandoned and lost, but being a Taggart, rarely lets it show except with girlfriend Holly. However, after they sleep together, Holly panics and breaks it off.
	Angela Perry (Tamara Craig Thomas) is in many ways the son Chuck never had; with the NASA career he wished Marc could have had. For her part, Angela is much more comfortable acting as Chuck's right hand than she is being the daughter of Senator Brian Perry. Grounded after she comes "back" in the middle of a space walk, confused and unaware of what has happened to her, she resents her father pulling strings to get her back on the roster, and does her best to throw a monkey-wrench into his life in retaliation. Angela and Kurt Mendel had a romantic relationship in the past which she ended without explanation, following an unplanned pregnancy she kept secret from him. A woman very much in a man's world, Angela is tough, and determined to be accepted for who she is and not her father's wealth or power. She's the most likely to rush in, guns blazing and, like Chuck, tends to keep her personal feelings to herself.
	Sarah Forbes (Leslie Silva) joined the Odyssey crew as an anchor at a cable news network, because she thought the mission might bring her closer to God and her son Corey, who had died shortly after his fifth birthday. Upon her return, she immediately begins taking Corey to doctors to try and prevent his death by stomach cancer, which causes tension between her and her husband Paul. Nothing is as important to her as her son, and she will do anything to protect him, even if it means the destruction of her marriage. A devout Catholic, Sarah is conflicted over her relationship with boss Troy (who in the original timeline became her second husband after her marriage with Paul fell apart after Corey's death). Smart, resourceful, and a natural leader, she is in many ways as vitally important to the group as Chuck, particularly as her job as anchor of the nightly news in Houston opens doors which would have otherwise remained closed to the group as they attempt to ferret out the truth regarding the Cadre and the Sentients.
	Dr Kurt Mendel (Sebastian Roché) may seem like a hedonist who would "follow [his] dick off a cliff", the Nobel Prize winning geneticist is a good man to have in your corner. Brilliant and cynical, he often clashes with Chuck. But when push comes to shove, he's an invaluable asset to the team. Despite the bevy of beauties which traipse through his apartment and his life, Kurt still carries a torch for Angela, and was deeply hurt by her breaking off their relationship just as he was realising he was in love with her. A scientist, he's aware that his insatiable curiosity may prove dangerous, but he is unwilling to give up studying the synthetics, because he believes it's better to know the enemy than be taken unaware. he's always the first to cloud the issue, and introduce a new point of view, and despite his frequent blow-ups with Taggart, he's fiercely loyal, and shares a bond with scientifically-minded Neil.
	The Seeker (John Neville) is a Sentient from a civilisation roughly 5000 years more advanced than our own which didn't use names but identified themselves by their life purpose, hence his referring to himself as The Seeker. He is the last remaining inhabitant of his world. Three hundred years ago The Seeker was sent on a quest to locate other civilizations, but whenever he went there was only dust and when he returned to his own home world he found the same, and has been searching the galaxy ever since. The Odyssey crew were the first survivors the Seeker found, and used his abilities to download their 2007 information patterns into theri 2002 bodies in order to try and alter the time stream to prevent Earth's destruction.
	Paige Taggart (Gina Clayton) met a brash young pilot in a train station in the late 1970s and they married the following year. For almost 25 years, Paige has been Chuck's partner, his lover, and his best friend. As one would expect of any woman who would choose Chuck as a husband, she's strong-willed and capable of holding her own against him if she has to. Her pride and joy is her eldest son Marc, and she and Chuck have hopes that he will become an astronaut like his father. However, she's unaware that the pressure this puts on Marc is too great for her son to handle. Likewise, she looks at their youngest son, and sees only a screw up who listens to heavy metal music, smokes pot, and ditches school. However, despite all that, she genuinely loves her family and would do anything for them. When Chuck and Neil begin behaving strangely, she gropes for an explanation to somehow justify their behaviour, unwilling to believe Chuck's wild story about being from the future might be true. However, when her mother becomes ill, and Chuck appears to have genuine knowledge regarding the "future" she tries to open her mind up to the possibility that her husband and son truly are from five years in the future. She is just beginning to accept the fact when she is tragically killed.
	Marc Taggart (Kenneth Mitchell) joined the Air Force because it was the family business. He joined the astronaut programme because it's what his parents wanted for him. However, he knows he can't cut it, and the crushing weight of his parents expectations only makes his descent into failure worse. In the original timeline, he borrowed money from his brother Neil and then took off when it became clear he was washing out of the programme. In the new timeline, Neil refuses to give him money but does try to help him with his Applied Physics exam. Marc resents the fact that what he has to work laboriously for seems to come so easily to his supposed screw up kid brother. Feeling frightened and alone, he lashes out rather than being grateful for the help. When he is approached by Flight Director Hodge and offered a chance to remain in the programme in return for spying on his father, he reluctantly agrees. However, following the death of his mother, a furious Marc leaves.
	Jenny Taggart (Victoria Snow) is Chuck's elder sister. Growing up, Chuck resented the fact that Jenny could do whatever she wanted, while so far as his father was concerned, Chuck lived "in the land of 'No'." Jenny was hurt and angry that 15 years earlier, Chuck did not attend their father's funeral. While she kept in contact with Paige over the years, she and her brother remained distant, unable to talk to one another without having a shouting match. At Paige's funeral, Neil takes her aside and tells her fifteen years is too damned long to hold a grudge. Impressed by her nephew, she gives it another try and she and Chuck manage to put some of their baggage behind them.
	Leyton Scott (Geoffrey Lewis) is Chuck's mentor. One of the original Apollo astronauts, Leyton is the first to tell Chuck about the secret society within the agency that he calls "The Cadre." Leyton tells Chuck that he is dying from "moon sickness", however his daughter Caitlin later tells Chuck that her father has Lou Gherig's disease.
	Caitlin Scott (Lyn Mason Green) is Leyton's daughter and keeper. She has mastered the fine art of the Southern Belle--that is to say, she'll smile sweetly and offer you a glass of lemonade while plotting behind your back. She seems determined to keep her father away from Chuck, but whether or not she is a member of the Cadre or working for the Sentients, is unclear.
	Matt Walsh (Craig Eldridge) died in the original timeline when the shuttle was damaged and almost destroyed following Earth's implosion. In the new timeline, Matt is alive and well and having been at Johnson Space Center the night Angela froze during a routine space walk and almost endangered her crew, he is angry that her father pulled strings to get her back on the roster. They clash while assigned to the International Space Station.
	Cynthia Hodge (Sonja Smits) becomes NASA flight director following Ed Scrivens' death. She often clashes with Chuck over her staunch belief that manned space-flight is a thing of the past. A member of the Cadre, a secret government group formed to fight the Sentients, she suspects that Chuck and Angela Perry are somehow involved with the failure of stage one of the Bright Sky project, and enlists Marc Taggart to gain proof.
	Penny (Suzanne McKenney) is a waitress at the diner where the Odyssey crew hang out and plan and discuss their missions. She and Chuck hit it off one evening, several weeks after Paige's death. She looks at Chuck and likes what she sees and isn't shy about letting him know it.
	Holly Culverson (Lindy Booth) is Neil's girlfriend. She's confused by Neil's behaviour, as he seems disinterested in the music he used to like, friends he used to have, and though he tells her that he loves her, rarely has any time to spend with her. At first, she likes this new "centred" Neil. However, she begins to feel like she's some sort of annoyance to him, as he breaks dates and doesn't return her calls. After she almost died, thanks to the drug rapture, they saw less and less of each other. After Neil's mother is killed, she tries to regain the closeness she felt with Neil while doing rapture by sleeping with him. However, confused and hurt, she accuses him of using her for sex and breaks it off completely.
	Kelsey (Mathew Langford) and Bodanis (Jonathon Langford) are classmates of Neil's. The identical twins are computer hackers, whom Neil enlists to help break the encryption on Naron Chandra's laptop. Without Neil's knowledge, they made an copy of the contents of the laptop, and shared the contents with Justin Deckard. Bodanis becomes hooked on a designer drug Deckard creates, using a link he found via the laptop, and is saved by Kurt and Chuck. The twins built a server for the high school computer class they dubbed "The Twinternet" which they then helped Neil use to trap the sentient who called herself Kitten.
	Senator Brian Perry (Barry Flatman) firmly believes that politics is a dirty sport, especially when played on television. And he's not afraid to get his hands dirty to win, provided he doesn't get caught. Unbeknownst to his daughter, he is a member of the Cadre, and Bright Sky is his project. When several assassination attempts are made on his life by a Sentient known as "Kwan", Angela is then kidnapped by a group of synthetics and he is desperate to see her returned safely, despite their differences.
	Enrique Peña (Bronson Picket) is a baseball player who approaches Angela outside an event one evening. In the original timeline, she was seeing Kurt at the time, and brushed Peña off, however, in the revamped timeline, the two begin a relationship.
	Corey Forbes (Amari Myles) is Sarah and Paul's son. In the original timeline, he died not long after his fifth birthday of a rare form of stomach cancer.
	Paul Forbes (Phillip Jarrett) is Sarah's first husband and Corey's father. In the original timeline, he and Sarah divorced not long after Corey's death. In the re-vamped timeline, he takes Corey and files for divorce when he discovers that Sarah is giving Corey unprescribed medication. When he discovers his mother is allowed Sarah to have unsupervised visits with Corey, he disappears. However, the courts rule he's in violation of the custody rights. He reluctantly allows Sarah to see Corey, and is then horrified when Corey is diagnosed with cancer.
	Mary Forbes (Sandi Ross) is Paul's mother and Corey's grandmother. When Paul files for divorce and wins sole custody of Corey, Mary takes care of her grandson during the day. At first wary of Sarah, she goes behind her son's back and allows Sarah to see Corey.
	Troy Johnson (Jim Codrington) is the news director at KNBS and became Sarah's second husband in the original timeline, following her divorce from Paul. In the revamped timeline, he breaks off his engagement to a woman named Cheryl because he's drawn to Sarah. He later proposes to Sarah, who accepts. However, it is unclear where the relationship will go, once Corey is diagnosed with a rare form of stomach cancer.
	Cheryl (Patrice Goodman) was Troy's fiancée. When Troy broke off the engagement, Cheryl blamed Sarah and told her to stay away from him.
	Kayli Haynes (Chantal Quesnelle) takes the job as KNBS co-anchor because she sees it as her ticket to the big time. Blonde, blow-dried, a little ruthless, and a little shallow, she is perfectly willing to smile at Sarah while she readies the knife to plunge into her co-anchor's back. She also has her eye on "cameraman" Neil, despite the fact that technically, he's still in high school.
	Chad Daniels (Jonathan Higgins) is the station manager at KNBS and Sarah's boss. He indulges her because she (usually) delivers the goods. Occasionally, he is utterly confused by her prescient knowledge, but so long as they ratings are up, really doesn't give a damn.
	Dr Lynn Chen (Jean Yoon) is a friend of Sarah's in the ME's office.
	Naron Chandra (Damon D'Oliveira) was a member of a think-tank which lasted for approximately six months. The group was developing artificial life or "A-life" using computer programmes. Chandra discovered that beings he called Sentients which had evolved from his programmes were loose on the Internet. In the original timeline, he burst into a symposium where Kurt was giving a speech and put a bullet in his brain after quoting Hindi epic poetry. In the revamped timeline, he aids the team until he is murdered by a synthetic in a parking garage.
	Dr Leshawn (Clé Bennett) is Kurt's go-to guy for all things bio-engineering related. So far, he's seen nanites, an addictive drug which for all intents and purposes causes ESP, and an enzyme which drives men to murder. There is not quite enough pot in the world for him to be able to handle some of this stuff, but he's willing to try.
	Claire Ambrose (Michele Doquet) is the mother of a 16 year old boy named Zach who remains in a coma after being attacked by Kurt's synth. Wracked with guilt, Kurt visits the boy in the hospital under the pretense of being a substitute science teacher at Zach's school, and forms a relationship with his mother, Claire.

Sentients are inorganic life-forms. The Apollo astronauts brought back a rock from the surface of the moon which originated on Mars and contained sentients from Mars. Sentients feed on information, and produce synthetic human-appearing avatars called in order to interact with the world. The Seeker and the Traveller took human form in order to interact with the Odyssey team, while The Collector appeared in a simulation as Paige Taggart. Harry Mudd downloaded himself into a stolen synthetic body, while Phaedra, Kitten, and Kwan have appeared only as graphical representations on a computer. While Phaedra did attempt to destroy the Earth by taking over a physics experiment and altering its data, it is as yet unclear whether Sentients were responsible for the Earth's destruction in the original timeline.
Synthetics or "Synths" are human-like synthetic bodies which a sentient uses in order to interact with the human world. Synths appear to have individual personalities, but are connected to their sentients via a hive-mind. Their body temperature is significantly lower than that of a human, which means they can be detected using thermal imaging cameras. They are fast, strong, and difficult to kill. One sentient used nanites like a virus in order to take over and convert humans into synthetics.
Seconds before the Earth exploded, the satellite which the Odyssey shuttle team had hung in space received a signal from Earth containing the word "Leviathan." The satellite was part of a Department of Defense programme called "Bright Sky." In the original timeline, Chuck knew about Bright Sky only as an "orbital physics experiment." He alone of the O5 shuttle team was aware that the project was from the DoD. In the revamped timeline, when Ed Scrivens investigated Bright Sky, he was murdered by a sentient using a group of gene therapy patients to construct synthetics in a lab located in a warehouse outside of town. Following Scrivens' death, Hodge assumed his position at NASA and fast-tracked the Bright Sky programme, launching the first satellite three years ahead of schedule. When Chuck and the team sabotaged the Bright Sky 1 module so that it did not achieve a stable orbit, the programme was stalled but not abandoned. Hodge and the Cadre have proof of Chuck's tampering, but they do not yet know why. Unbeknownst to Angela, her father is shepherding Bright Sky personally, and it is most likely the reason the sentient known as Kwan tried to assassinate Perry.
The Cadre is a clandestine organisation consisting of NASA, military, and political figures including NASA flight director Cynthia Hodge and Senator Brian Perry. The group was founded with one sole purpose: the eradication of the Sentients in order to preserve the supremacy of organic life on the planet. While they are aware of Sentients and synthetics, they do not yet know where the Odyssey team fits into the grand scheme of things. They are currently engaged in a five year plan, of which Bright Sky is an integral part, to achieve their goals.