The president of the United States declares there's a comet heading for Earth that will end all human life in 34 days.
Jamie Winton (Mathew Baynton), a boring, predictable bank manager is arrested under the suspicion that he is The White Horse, leader of the elite hacking squad Deus Ex Machina. The police show Jamie a photo of The White Horse and it looks exactly like him. Even more shocking, the police have a photo of him in Moscow six weeks ago with Jamie's wife, Layla (Karla Crome), who has been missing for seven years. With a watertight alibi, the police release Jamie. Back at home, Jamie's mother, Paula (Pauline Quirke), tells him he's adopted. Hoping he has a twin he doesn't know about, Jamie goes back to the police station, but finds it mostly evacuated after the announcement of the comet. He gets the photo of his wife - the only clue he has to find her.
Rhonda McNeil (Jenna Fischer), charged with treason for hacking the NSA, enters a maximum-security prison. Her lawyer is unconvinced Rhonda is a hacker and wants her to stop protecting her son, Spike (Fabian McCallum). With Rhonda in jail and her husband in the hospital, custody of Spike is given to his biological father. During the pandemonium following the president's announcement, Ariel Conroy, aka The White Horse (Jamie's twin brother), busts Rhonda out of prison believing she hacked the NSA. Seeing her ticket out of prison, white supremacist Leanne (Megan Mullally) handcuffs herself to Rhonda, forcing Ariel to take her too.
Wanting more than just a life in the convent, Sister Celine (Gaia Scodellaro) interviews for a job at the Vatican with the Devil's Advocate, Father Jude Sutton (Rob Lowe). He offers her the job, but she needs to pray about it. After she hears the announcement of the comet, she takes it as a sign from God and accepts the job with Father Jude.