After a long flight, the spaceship that Ripley (Sigourney Weaver) was on did not fly back to Earth! An accident occurred on the way back to Earth, and the cryogenic hibernation capsule separated from the main ship before the mother ship exploded and fell into a dark and cold planet. In addition to the remaining bishop, only Ripley survived. This is an abandoned alien mine on Earth, which has now become a prison for dangerous prisoners. Ripley recovered with the help of a doctor. With the arrival of Ripley, the prisoners here began to be mysteriously killed one by one. The authorities thought it was a crime committed by the prisoners, but Ripley knew it was not that simple. When she found the remains of the bishop and connected it to the computer to check the flight records, she confirmed her idea: the aliens are coming.