In 1943, the USS Eldridge was made invisible and teleported from Philadelphia to Virginia. This event was known as the Philadelphia Experiment.

When the Eldridge reappeared, some crew materialized in walls and bulkheads. They died in agony.

But two sailors didn't reappear at all. The two men, who happened to be brothers, were presumed dead or lost.

They weren't dead. 

They traveled 40 years into the future; in a secret military base on the East end of Long Island.

They became unwitting participants of The Montauk Project.