The TARDIS lands on the idyllic jungle world of Deva Loka, which is being surveyed for possible Earth colonisation. Deva Loka is already home to a race of apparent savages, however: a mysterious people with strange powers which have mentally unbalanced the members of the expedition. To make matters worse, an ancient enemy of the natives known as the Mara is intent upon revenge, and latches onto Tegan's mind as its bridgehead to victory.
Danny Duggan runs a failing building contractors, and resorts to sub-gangster thuggery to keep the business afloat. However, with the bottom falling out of the building game, Duggan finds that playing at gangster is only fun when you're on the winning side.
