Based on an "actual event" that took place in 1943. About a US Navy Destroyer Escort that disappeared from the Philadelphia Naval Shipyard, and sent two men 40 years into the future to 1984.

A secret government research project tries reviving the World War II "Philadelphia Experiment," which was an attempt to create a cloaking device to render warships invisible. When the experiment succeeds, it brings back the original ship (the Eldridge) that disappeared during the first test in 1943 - which brings death and destruction to the 21st century. It's up to the sole survivor of the first experiment and his granddaughter to stop it.

It is several years after the events of the first movie, and David Herdeg (the survivor of the Philadelphia Experiment from the first film) and Allison (the woman from 1984 he fell in love with) have married and have a child. David awakes, in agony, to a changed world. Germany won World War II and the United States is now about to mark 50 years as a Nazi conquest.