The crew of a routine space shuttle mission bear witness to an extinction-level event on the planet Earth, only to find themselves five years into their own past -- with a chance to prevent the end of the world.
The team's attempt to stop a paranoid scientist from killing himself leads them to discovery an artificial intelligence, which may have a connection to the end of the world. Sarah and Angela investigate a suspicious gene therapy treatment, and Neil returns to high school.
When a predecessor to the secret "Bright Sky" satellite is schedule for orbital deployment, Taggart looks for a way to get himself assigned to the mission. Sarah and Angela try to stop a child abduction before it happens, and Kurt comes up with a way to detect synthetic lifeforms.
When the crew of the Odyssey begin to forget their memories of the future -- including their relationships and their mission -- Chuck and Kurt soon find themselves racing against fate. Meanwhile Kurt marries a future musical superstar, hoping to cash in on her coming fame.
Chuck and Kurt go in search of the deaf niece of a scientist involved in advanced cyber-biology research. Sarah meets her future husband from the original timeline, and Angela confronts her father about his actions and his political ambitions.
After a mysterious man appears to the members of the Odyssey crew, they are forced to confront tragedies from their past. Sarah pursues a new medical treatment for her son, and Angela reconsiders her relationship with Kurt.
Neil learns that a new drug his high school peers are using is giving them psionic powers, and may have a connection to the crew's mission. Chuck grows suspicious of forces inside the space program who are trying to end manned space flight.
Sarah takes Chuck and Kurt, posing as a camera crew, inside a high-security prison in order to meet a convicted murderer who has encountered synthetic lifeforms. Neil tries to help his brother with a problem.
An encounter with an infected man leaves Chuck undergoing some sort of bizarre transformation, further complicating his marriage. Sarah finds herself in a custody battle with her husband, and Mark gets an offer.
Neil's late night online flirtation turns into a fatal attraction -- and the girl who is stalking him is an artificial intelligence with resources networked around the globe.
Chuck and Neil go in search of Kurt, who has been drawn to a small town in west Texas where the local residents have become fanatical adherents to an ancient Babylonian religion. Angela decides to intervene when she remembers an incident her father tried to cover up.
Angela introduces the group to an odd man who turns out to be a synthetic being, who is now on the run from the alien Sentients -- and who comes with a warning about experiments that could threaten the planet.
The team tracks a synthetic organism that leeches onto its victims and controls their bodies, and which has its sights set on assassinating Senator Perry.
Kurt's attempt to grow his own synthetic lifeform has unexpected results, leaving the creature on the loose and Kurt mentally unstable. Meanwhile a devastated Chuck hits the open road, where he meets a young hitchhiker.
Mourning the loss of his wife, Chuck wakes up in a world where she is still alive and well. Meanwhile Sarah and Angela investigate a string of bodies connected to the transhumanist movement.
After a 10-year-old boy is arrested for murdering his sister, Sarah and Kurt pursue a potential connection to a previous murder -- and the mysterious "Leviathan." Chuck has to deal with family issues when his estranged sister shows up at his door.
Angela feels as though she is being haunted by a ghost, only to discover that someone from her past is trying to reach her. Sarah introduces Troy to her son, and Chuck considers a new relationship.
The shocking murder of Dr. Chandra sends the Odyssey crew to the suburban town of Lawndale, which is being plagued by a string of unexplained murders by ordinary people.
Angela is abducted in a confrontation with a group of Synthetics. As the rest of the team searches desperately for clues, Chuck sets his sights on a mysterious rock retrieved from the Moon decades ago -- which may be connected to the origins of the Cadre.
