When a malfunction occurs aboard the luxury space cruise ship Avenue 5, it's up to engineer Billie McEvoy to warn Capt. Ryan Clark, owner Herman Judd and his right-hand woman Iris Kimura that the incident may have a cataclysmic knock-on effect.

Rav and her team meet with a NASA representative to plot a potential rescue mission. An engineer working in a hidden part of the ship has a surprisingly optimistic theory about the ship's future. Karen becomes a vocal advocate for passengers.

Billie seeks her moment in the limelight after stepping in to help Ryan during the ship's newest crisis. Iris vets comedian Jordan Hatwal's material for the Halfway Home Party, which Judd has decided should go on as planned. Doug tries to get in the way of Mia's newfound sexual freedom.

After five long months, the passengers of Avenue 5 eagerly await their impending return to Earth­­ while behind the scenes, Ryan and the crew struggle to find a way to reveal the much longer timeline of their journey home. Later, a disgraced Karen comes to blows with a newly famous Frank.

The crew turns to a Judd-designed ranking algorithm to deal with their latest threat. As Ryan’s rating mysteriously tanks, Billie searches for her more worthy counterpart, and Judd attempts to make amends with an estranged Iris.