Holy crap. This was actually a really interesting episode that blew the lid off the show and introduced what it was really about! So back in the 70s, Walter Bishop discovered the multiverse and that visitors from a parallel universe were crossing over into our world and were going to destroy it, so he wrote a book about it, then lost his memory and got institutionalized. And now the "bad guys" (Massive Dynamic I assume) are training humans to be psychic warriors to fight the parallel-humans. I assume the Observer (who I finally noticed in a cameo!!!) is a good guy parallel human. I doubt anyone else is aware of this but Jeff Smith's new comic RASL has the same premise.