This interesting genre-jumping sci-fi/horror film plays much like a low-budget derivative of Alien and The Thing with a clever occult twist. The story takes place in lunar orbit, where a maintenance spaceship becomes marooned after a mysterious accident. Cut off from Earth contact and rapidly losing power, they encounter another derelict craft and its dead, mutilated occupant. They board the other ship to draw on its power plant, taking the corpse aboard for study, and soon discover that the ship was part of the U.S. Discovery program, reported lost after splashdown in the Bermuda Triangle -- at a point in direct line with the moon's dark side. Unfortunately for the crew, the significance of this correlation is discovered too late, as the evil force residing within the dead spaceman's body emerges to take possession of the crew's souls. This leads to a confusing game of "musical souls" as the paranoid survivors turn on each other, never sure which of them is acting under demonic influence. Although not particularly an original concept, this is still a very tense, nightmarish film, with high production values, claustrophobic atmosphere and some nail-biting moments. The filmmakers' attempts to communicate the crew's increasing confusion and paranoia are quite effective, though things go a bit overboard at the climax.