In 1943, U.S. Navy sailors David Herdeg (Michael Paré) and Jim Parker (Bobby Di Cicco) are stationed aboard the destroyer escort USS Eldridge. As they are docked in Philadelphia, Doctor James Longstreet (Eric Christmas) performs an experiment that is supposed to render the ship invisible to radar, but the ship up and disappears. David and Jim jump overboard to escape.

They find themselves in a small town, which also disappears, and they are marooned in a desert. Startled by helicopters, they run and Jim is nearly electrocuted by an electric fence. Finding themselves in a roadside diner, Jim somehow produces an energy discharge that destroys two arcade games and the angry manager pulls a gun on them. Escaping into the parking lot, they take Alison Hayes (Nancy Allen) hostage and force her to drive them off in her car. They are shocked to learn that it is 1984. They are arrested by the police, but Jim is put in the hospital because of his seizures. He vanishes in a flash of light, and David and Allison run from the military police.

They learn that they are near California, where Jim was born, and David tries to find Jim’s family. Jim’s wife Pamela (Louise Latham), now elderly, recognizes David from 1943, and tells him that the Eldridge had reappeared shortly afterward. Jim reappeared too but David did not. He sees an elderly Jim, but Jim refuses to speak to him after his years of trauma. They escape the authorities again after a high-speed chase. The pursuing police car crashes and burns, but David retrieves some documents mentioning Doctor Longstreet, and David decides to find him. By now, David and Allison are becoming an involved.

In 1984, Longstreet has been trying the same experiment, hoping to protect America from an ICBM attack. Tis one goes awry too. A town disappears into hyperspace and a vortex begins pulling matter into it and causing storms. Longstreet fears the vortex will expand to swallow the Earth. Scientists send in a probe and discover the Eldridge inside. They believe the vortex is using the generators aboard the Eldridge for power.

David captures an assistant at Longstreet’s home and forces him to take them onto the base. Longstreet explains what is happening and tells David that he must enter the vortex and finally terminate the experiment on the Eldridge. He is given an insulated suit and catapulted into the vortex, landing on the Eldridge’s deck. He enters the generator room and smashes vacuum tubes with an axe. When the generators shut down, he finds Jim, then jumps over the side and disappears. Some crew have been fused into the ship. In 1984, the town reappears, as does Jim, and the lovers get together.

The film was directed by Stewart Raffill, based on an urban legend. John Carpenter wrote the original draft of the script, but it was rewritten nine times. The Eldridge was played by the USS Laffey in South Carolina, but the film was shot in various places, including the Bonneville Salt Flats. Nancy Allen was nominated for a Saturn Award. John Carpenter was asked to produce, but he suggested Escape From New York instead and Embassy Pictures went with that. The explosion of the buildings was arranged with a town in Utah which wanted to clear some abandoned buildings for a new sewage system.

The story that this was based on a real-life experiment in the 1940’s is fake news spread by an eccentric named Carl Allen. It is still believed by many, on the grounds that the lack of evidence means the truth was covered up. The US Navy did not support the film because they wanted nothing to do with the fakery. There was, in fact, a procedure on the USS Engstrom to make it invisible to mines and torpedoes by the use of a powerful electromagnetic field, created by Charles F. Goodeve of the Royal Canadian Naval Reserve. The device worked and was used during World War II.