So, this is the bug episode with the big shocking twist which everyone (including our regular recapper) saw coming a mile (or at least the larger part of a season) away.
At the church, Dexter frees Travis from his shackles and tries to predict the location of the next tableau so they can stop Gellar. Travis plays the shell-shocked victim and is utterly useless, but Dex sees “2LoT” written on a painting and a matching parking pass, and with some Internet searching, it looks like a Professor Casey (an atheist) is the next victim. Dexter also takes Travis and puts him in a safe hotel room, so that Gellar can’t get to him. But that doesn’t stop Gellar from blogging about false prophets (Dexter) and returning to the fold or whatever.
Dexter goes back to college and listens to Professor Casey’s lecture and figures out a plan to save the dude. So he grabs Travis, they go back to the school late at night, split up (really?) and Dexter ends up trapped in an elevator because he’s too damned lazy to run up the stairs. Naturally, Travis saves him, but its too late for Prof. Casey, who has had his hand chopped off and has turned up dead. His hand is in Travis’s hotel bathroom, with a bloody message on the wall. Hope Dexter doesn’t have to pay that security deposit, because blood on yellow walls has got to be a bitch to get out.
Dexter is still bound and determined to save Travis from his dark passenger (to somehow prove that he’s a good father), so they return to the church where they split up (again!) and Travis ends up unconscious on the floor, and Dexter stumbles down to the basement to find Gellar’s body in a freezer, where it has been for quite some time. Turns out that Gellar was Travis’ dark passenger, but not of the actual alive kind and that Travis is the Doomsday killer all by his very lonesome. Since we’ve seen The Sixth Sense, this really comes as little surprise. Still, its nice to know that someone gives the killer figment of their imagination a kindly Mr. Rogers sweater.