The spacecraft Odyssey II is set to embark on a mission to retrieve a foreign object that could potentially save mankind, but the plan quickly goes awry when five untrained kids sneak aboard and are unable to stop the launch sequence.

Tension on the ship rises as Elliott plants seeds of distrust about Will, whom Elliott suspects is collecting mission information for his reporter mother. Meanwhile, Samy works with Matilda’s inventor to probe the AI’s role in the accidental launch.

A small toy clogging the toilet leaves only one working bathroom as the kids work together to dislodge it. On Earth, tempers flare between the parents while Matilda's inventor devises a bold plan to hijack the AI.

Mission Control uploads a virus onto the Odyssey in an attempt to take control. Matilda fights back by shutting everything down, and the true vulnerabilities of the kids comes to light.

A small hole in the ship threatening the oxygen supply can only be repaired from the outside, forcing Martin to become the first kid to ever attempt a spacewalk.

With morale at an all-time low, Elliot takes it upon himself to rally the group with a team-building exercise involving using a high-tech camera to make a movie: a space movie.

Day 76: Mission Control implements a new plan of attack: unplugging Matilda from avionic control and transferring it to the ground. In the middle of this task, Samy has to undergo emergency surgery without the aid of a medical professional onboard.

Mission Control failed to transfer control to the ground, which means the kids are now driving the space craft. With only one day of training, the kids must steer a spacecraft into Venus's orbit without it burning up in the planet's atmosphere.

An unexpected development prompts doubts among the kids about returning home, and an unknown threat attempts to destroy the Odyssey before the astronauts can make their next move.