There were the contracts, the agents, the local sponsors, the broadcasts, the laws which made murder legal...

It had taken a long time to establish, and an even longer to develop the league of superstar duellists. And just when it was all working so well, someone or something started interfering. Famous fighters died in private duels. Up-and-coming professional fighters fell to casual, one-time challengers.

When Leela is challenged to a duel to the death, the Doctor realises that there is more to the situation than simple murder and mayhem. But before he can sort it out, he needs to save his client — Leela. How long can she survive on a planet where to not kill is an offence punishable by death?