The crew of HMS Camden Lock start negotiations with various alien civilisations to sell blocks of the Peterborough Enterprise Zone. When things fail the first time, Space Force demands that Commander Henderson and his crew have to find another buyer within a week. The task doesn't get easier with an alien killer machine on board and the navigation system dropping out.

Vine buys a planet while Teal contrives to be alone with Henderson at the officer's ball.

The crew of HMS Camden Lock are subjected to an extremely strict assessment test causing Henderson to seek the solitude of his cabin leaving York in command.