A rocket carrying three astronauts is launched by an American scientist, Brain Donlevy, but only one makes it back – and he’s in terrible condition. The film explores what occurred to the missing crew members, considering the possibility that the spacecraft was airtight. Alongside a police officer named Jack Warner, investigators attempt to uncover the truth. Simultaneously, the lone survivor disappears, leading to the discovery of an alien being now roaming postwar London, driven by hunger. A frantic effort begins to prevent it from reproducing and dominating the planet, with a dedicated group tasked with hunting down and eliminating this threat. Despite its modest budget, the movie boasts strong writing and direction, employing inventive cinematography that avoids the rigid, scene-by-scene presentation common in many British films of the 1950s. Two compelling performances help maintain the suspense throughout.

Source on TMDB