Fleming and Andromeda are being hunted both by the British Government and by the Intel trading consortium, who are developing another supercomputer in the newly-independent Middle Eastern country of Azaran.

The Intel trading organization have kidnapped biochemist Madeleine Dawnay and physicist John Fleming and want them to work for them. Something strange is happening to the world's weather, and Andromeda's health is failing.

The Intel trading consortium has backed a military coup in Azaran. Mlle Gamboule has been drawn to the computer by Andromeda who, apparently dying, is determined to work out the purpose of the message from space.

The alien enzyme is causing the Earth's atmosphere to get thinner, and violent storms are sweeping the world. Intel get the scientists to develop a solution, to be sold on their terms. A counter-revolution led by the former president overthrows the rebels and Intel.

Fleming and Dawney work on a formula to restore Andromeda to health. Andromeda deciphers the signals, but can Earth be saved?