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.

Judd outlines the plan for a rescue mission and tasks Iris with organizing a vigil on Earth to raise the money to fund it. Rav endures a barrage of messages from the ship and handles an unruly press conference.

With Judd worried about his reputation, Iris arranges a meet-and-greet with several passengers in his luxury suite. Frustrated by a bridge crew with no answers, Ryan and Billie bond with the engineers below deck.

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.

Judd enlists Ryan to help charm Harrison Aimes, an uber-wealthy passenger who has a strange effect on Judd. Meanwhile, the passengers become transfixed by a divine image circling the ship and Rav deals with the fallout when the ship's moral quandary hits the media.

While Karen oversees an effort to jettison non-essential passenger items, Billie tries to teach an inattentive Ryan how to dock the ship. Matt learns of Judd’s plan to make the “ultimate sacrifice” by returning to Earth. Meanwhile, the passengers suspect all is not as it seems with the journey.

A search party commences for Matt, who’s in hiding with a guilty conscience – and the airlock codes. Iris questions Karen about her rumored affair with Ryan. Rav seeks an apology from Judd for ruining her life, as chaos ensues when a seat on a rescue shuttle suddenly becomes available. Season finale.