As a comet heads toward Earth, an unlikely group of survivors takes refuge in a bunker underneath the town of Slough. Jamie makes a discovery about his wife, Sister Celine leaves the convent, and Rhonda struggles to survive in prison.

With the population in chaos as the comet's approach sparks riots, Jamie begins a hapless hunt for Layla; Father Jude is given a crucial new role.

Jamie's search grinds to a halt when he is yet again mistaken for Ariel; Father Jude and Sister Celine help a young girl escape an angry mob.

Rhonda horrifies herself when she realises she'll do anything to keep her freedom; Ariel stumbles onto United States government's biggest secret.

Jamie makes a discovery that leaves him feeling betrayed; Ariel sends Scotty a worrying message; Rhonda realises no one can be trusted.

Scotty attempts to make amends for his recent decisions; Jamie's life receives a shake-up after a sudden tragedy.