The "Event Horizon" is a spacecraft designed to travel faster than the speed of light by creating a black hole and then using it to fold space. The ship was believed to have disappeared while on its maiden voyage, with all the crew members presumed dead.
Seven years later, the ship suddenly reappears in orbit around Neptune. A rescue vessel, the "Lewis and Clark," is sent to investigate and salvage the vessel. The crew of the "Lewis and Clark" includes Captain Miller (played by Laurence Fishburne) and Dr. Weir (played by Sam Neill), the designer of the "Event Horizon."
As the crew explores the ship, they begin to experience strange and terrifying phenomena. They discover that the "Event Horizon" did not simply disappear, but had instead gone to a place beyond our world, a place of chaos and darkness that had driven its crew insane and led to their deaths. The crew begins to suffer from hallucinations and violent outbursts, leading to a breakdown in their relationships. Dr. Weir, who had lost his wife to suicide prior to the "Event Horizon" mission, begins to experience terrifying visions of her.
It is eventually revealed that the ship's experimental gravity drive, which created the black hole, had opened a portal to Hell. The crew must fight for their survival as they are pursued by demonic entities that have escaped through the portal. With the help of Dr. Weir, the surviving crew members attempt to destroy the ship and close the portal before it's too late.
The film is known for its graphic imagery and disturbing themes, and in its initial release, it received mixed reviews. However, over time, it has gained a cult following and is often regarded as a classic in the sci-fi/horror genre.