In the cutthroat world of international finance, a group of young graduates compete for a limited set of permanent positions at a top investment bank in London. The boundaries between colleague, friend, lover, and enemy soon blur as they immerse themselves in a company culture defined as much by sex, drugs and ego as it is by deals and dividends.

Mary Trewednack lives above her Post Office in the fictitious Cornish village of St Gweep with her neurotic partner Angela. Lesbians until something better comes up, they enjoy the cosy security of life in a tight-knit coastal community, but their chances of finding suitable men are more remote than the village itself. For, behind this picture-postcard exterior, witchcraft and wife-swapping are more a way of life than cream teas and Cornish pasties. Here, the village bobby is Police Calendar's Mr. March, the cosy pub hosts swingers' evenings and the local museum is dedicated to witchcraft.

Set in 1970, a team of scientists decipher a mysterious signal from space and discover that it provides instructions to build a powerful super-computer. Once built, this computer provokes argument between two of leading team members, Fleming and Dawnay, over the machine's real intentions as it provides further instructions to create a living organism, which Dawnay starts to develop. Later it appears to compel lab assistant Christine to commit suicide, and when the organism is fully developed, it appears in the exact form of Christine, and named Andromeda. But what is the purpose of this "creature" ...?