After having his spaceship wrecked by the dreaded finkumpoops, space pirate Captain Codswallop takes refuge on Earth and unwittingly brings three finkumpoops with him.

The finkumpoops are small furry creatures called Fink, Um and Poop who as well as being technological geniuses are complete idiots. They have a habit of taking things apart and putting them back together again in such a way as to make them do things they were never meant to do. Because of the devastation they cause, planets known to be infested with finkumpoops are invariable blown to smithereens by a fleet of Gorbanian battlecruisers – a fate that awaits Earth unless something is done to rid it of finkumpoops.

Robbie Callaghan is a schoolboy.

The summer holiday has just begun and he is already bored. Forced to flee his house to escape the attention of a couple of doting spinsters, he stumbles upon Hobb's End, an old station that has been converted into a home-cum-workshop by a stage magician who goes by the name of Manfred the Magnificent.