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, meanwhile, becomes a vocal advocate for passengers.

With staff slacking in their customer service, Ryan gives Karen the opportunity to channel her unique talent for speaking the passengers' language. Judd outlines the plan for a rescue mission and tasks Iris with organising a vigil on Earth to raise the money to fund it.

With Judd worried about his reputation, Iris arranges a meet-and-greet with passengers in his luxury suite. Frustrated by a bridge crew with no answers, Ryan and Billie bond with the engineers below deck. Matt encourages Frank to become the man he always wanted to be.

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. Doug tries to get in the way of Mia's newfound sexual freedom.

As Avenue 5 cheers the birth of a space baby, Ryan and Billie look for the source of an incessant beeping, and Judd shares his latest grand idea. In the nation's capital, Rav appeals to the President for rescue funds but, in exchange, is faced with an ethical dilemma.

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 items, Billie tries to teach 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 an affair with Ryan, as Rav seeks an apology from Judd for ruining her life. Chaos ensues when a seat on a rescue shuttle becomes available.

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.

With the ship facing a fiery threat, Billie hatches a plan that could just save some of the passengers… and the eels. Meanwhile, Iris makes a risky bid on Earth, Ryan finds himself in the middle of a three-way couples' quarrel, and Mia shares shocking news with Doug.

When the ship crosses paths with a rogue space station, Ryan and the crew jump at the opportunity to socialise. Then, after Rav discovers the true purpose of Storm Falcon's mission, Ryan must steer his team through a difficult moral quandary.

Now stuck with an unsavoury stowaway, Ryan and Billie lock down the ship - with potentially dangerous consequences. Meanwhile, Iris and Judd attempt to blackmail Lucas, Karen claws her way back to the top, and Frank fends off an attack.

After a failed revolt, the passengers put the ship's leadership to a vote, bringing forth a pack of unlikely candidates. Meanwhile, back on Earth, the Office of the Other President proposes a plan that could spell doom for Avenue 5.

With a "new leader" at the helm, life on deck reaches a semi-status quo - until the discovery of a mysterious blip and dissident uprising threaten to upend the passenger's tenuous peace. Later, life imitates art as TV's Avenue 5 puts those aboard the real ship in peril.

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.

With the ship divided, both sides find themselves in an all-out fight to survive. Then, Ryan takes part in a shotgun wedding, and Rav reaches a personal breakthrough.