Kidnapped by his oldest foe, the Doctor is forced on an impossible mission - to a place even the Daleks are too terrified to enter... the Asylum. A planetary prison confining the most terrifying and insane of their kind, the Doctor and the Ponds must find an escape route. But with Amy and Rory’s relationship in meltdown, and an army of mad Daleks closing in, it is up to the Doctor to save their lives, as well as the Pond’s marriage.

Orbiting a quiet backwater planet, the massed forces of the universe's deadliest species gather, drawn to a mysterious message that echoes out to the stars. And amongst them, the Doctor. Rescuing Clara from a family Christmas dinner, the Time Lord and his best friend must learn what this enigmatic signal means for his own fate and that of the universe.