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.

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.