While decommissioning an old nuclear missile, a simple accident causes Team Scorpion to endure exposure to toxic vapor while trying to prevent the nuke from detonating. Also, Paige confronts Happy about constantly tagging along with her and Walter.

Team Scorpion must work with Toby’s nemesis, Quincy Berkstead, and his wife, Amy, Toby’s ex-fiancée, when they are locked inside an artificially intelligent doomsday bunker that aims to kill them. Also, Walter is distracted by his recent dream where he is married to Florence, not Paige.