Dexter, using what he's learned from Brother Sam, comes a step closer to the Doomsday killers, specifically Travis; Deb and LaGuerta go head-to-head after a call girl ends up dead.

Now realizing the error he has made, Dexter redoubles his efforts to track down the doomsday killer and eliminate him. He plants evidence in the church to keep the police off the scent and sets out to find DDK. He manages to track down Holly, the woman Travis freed, but too late. From the evidence at the crime scene, Dexter believes he knows what DDK will strike with next, though he has no idea where. With Quinn hung over and not at work, Batista sets off to interview a person of interest which may have major ramifications for him. Meanwhile, Deb goes through the evidence from the dead call girl case and now knows who was with her and who Laguerta is protecting. Louis the crime lab intern is more than a little deflated when Dexter slams his new computer game.