The Terraphiles are a group obsessed with Earth's past and dedicated to re-enacting ancient sporting events. The Doctor and Amy join them on a trip to Miggea, a star on the very edge of reality, and venue for a competition to win the fabled Arrow of Law. But the Terraphiles' grasp of Earth history and customs is dubious to say the least, and just getting to Miggea is going to prove tricky.

For reality is falling apart, ships are disappearing, and Captain Cornelius and his pirates are looking for easy pickings. And the Doctor and Amy have to find out who is so desperate to get the Arrow of Law that they will kill for it.