Bernard Quatermass heads the futuristic Experimental Rocket Group whose greatest voyage is coming to an end, but after a dramatic crash landing Victor Carroon begins to metamorphose into a strange, deadly alien, setting off a race against time to save humanity.

In the Yorkshire Dales, a mysterious signal from space arrives with instructions to build a powerful super-computer. Once completed, the evice's motives provokes discourse between scientists John Fleming and Madeleine Dawnay as further instructions are to create a living organism, which Dawnay develops. The entity compels lab assistant Christine to commit suicide, and, upon manifestation, adopts her form, now known as Andromeda.