And Some Dude Named Jeff

S4, E10: The Librarians are about to go off on an exciting adventure. They tell Jenkins to set the Door, but when he does so, instead of Jenkins we see some other guy dressed in his clothes. The other Librarians don't seem to notice. Meanwhile, Jenkins wakes up in a strange bed. He's in some basement and in his closet there's just a bunch of heavy metal T-Shirts? He looks in the mirror and he's shocked! He's switched bodies with some schlub named Jeff.