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.

Henderson, Teal and York try to make first contact with the Queppu but are instead greeted by crossbow fire and are accused of being rebels. Meanwhile Jeffers, left in command of the ship, enters into a space race.

Henderson, miffed at being usurped by the Americans negotiating peace between two alien races, takes matters into his own hands with explosive consequences.

Henderson is invited to join Britains premier space-o-batics team (a Red Arrows for space) led by Squadron Leader Mason, who twenty years ago had a fling with Teal. Meanwhile, York reveals the results of his terrifying scientific experiment and Vine has enlisted Jeffers into injuring him in a 'workplace accident' so he can be sent back to Earth.

The daughter of the Space Admiral has run away avoiding university and Henderson is ordered to get her back. Meanwhile both Vine and Jeffers have taken a shine to the young student and fight for her heart in the only way they know how - a duel. Arabella steals a shuttle craft and elopes with Jeffers leading them both into mortal danger.

Entrusted with leading the convoy guarding Britain's new super-weapon, the Camden Lock's position is betrayed. There is a traitor aboard and all the officers are under suspicion. There is a desperate race against time to find the mole before Earth is destroyed.