The Doctor arrives in present day Iceland and receives a frosty reception from Inspector Yrsa Kristjansdottir when he becomes the chief suspect in a murder enquiry. But the Doctor knows that the real killer is of extraterrestrial origin.

Joining forces with Yrsa, the Doctor goes in pursuit of a ruthless alien that is hunting humans for sport. Yrsa unearths a dark conspiracy which reaches back into her own past.

Determined to expose the truth and prevent further deaths, the Doctor and Yrsa soon find themselves running for their lives, prey on the hunting ground.