This is one of those boy-did-I-get-a-wrong-number stories. An average Joe from 1959 accidentally gets connected to the switchboard of a mutant group planning to take over the world. They decide he's dangerous and knows too much, so they pop him into their time machine. In the future he finds himself surrounded by mutants (who now rule the world). They assume he's a spy, so they pop him into their machine…
Maybe I should explain that in the early days of telephones, the familiar seven-digit numbers used in the United States were organized into "exchanges", where the first two digits were given a mnemonic word; the first two letters corresponded to those numbers, and were generally capitalized. These exchanges were assigned geographically, so a small town might fall in the EXbrook exchange, and all the numbers in the town would start with 39.
