"For Services Rendered," last night's episode of "The Strain," doesn't push the story forward much, if at all. Especially in comparison to previous weeks, which rocketed us through the exposition like a vampire in search of a scrumptious carotid artery.

Really, our two major plot threads for the week were Eph, Norah, Setrakian and Jim (really, everyone who matters, at this point) trying to pull a double cross on ol' Eichorst, and the continuing saga of lawyer lady Joan Luss, who at this point is now fully a vampire, and fully in favor of chewing on both her husband and her children.

Our plot to distract Eichorst and repeatedly stab him doesn't even get us anywhere- after a tense confrontation on a subway platform, no one's any better or any worse for wear (Eichorst ends the scene by calling for the ancient vampire equivalent of a "do-over"). So really, the only forward momentum in "For Services Rendered" comes from the Luss family.

And boy oh boy is that ever some forward momentum. Seriously. A beautifully crafted, masterfully executed slam-you-in-the-head-with-a-question-mark plot twist to end the night on. Which we will cover... a little later on.

First up is our main thread- our heroes' plan to put down the vampire menace once and for all. Setrakian, last week, mentioned to his burgeoning crowd of vampire killers that he had a new plan. And now we know what it is.

The plan in question: kill the head, and the body will follow. And in this case, the head of all vampirism is The Master. But because no one has The Master's personal cell number on hand (and because ancient vampire overlords tend to have unlisted numbers anyway), our heroes settle for the next best thing: Thomas Eichorst.

"For Services Rendered" highlights an important part of "The Strain" that's become painstakingly clear. The Master might be the big bad (and that shot of him revealing his bald head will still show up in every "previously on" until the end of time), but Eichorst is the series' real main villain. For now, anyway.

He's the one we see doing all the villain-ing, the one tormenting various protagonists, week in and week out. He's also the one whose motivation and personality we know the best.

Case in point: a knockout series of flashbacks between Eichorst and Setrakian, back in their concentration camp days (with Jim Watson filling in as a young Setrakian). There's an odd familiarity that grows between them- a concentration camp gestapo and a prisoner vaulted into a position of slightly less torment.

They're far more comfortable in each others' presence than a Nazi and a Jew have any right to be (even though Setrakian still fears for his life at every moment, he's gotten comfortable enough to tell Eichorst his real thoughts on the Third Reich).

They drink (Eichorst, despite the war crimes, the vampire crimes, and the all-around creepiness, is a weirdly likable drunk), Setrakian hand-carves The Master's Dracula coffin, and we finally come to understand the long history these two display every time one of them mentions the other in present day.

It also doesn't hurt that the individual scenes (say, when Eichorst gives Setrakian a chance to grab his gun and die a warrior's death, which Setrakian shies away from) are as tense as anything with actual vampires in it.

Which, as far as anyone can tell, Eichorst is not- not at that point in the flashbacks, anyway. He consumes alcohol, not blood, and he seems to have a fully functioning set of genitals. He's definitely being wooed by the Master already- that much we can tell.

These flashbacks are as compelling a series of scenes as "The Strain" has ever put out. And as a bonus, they give a little (well, a lot, really) extra oomph to the confrontation between the two at the end of the hour.

So what if Eichorst's slow-mo run and claw-latch onto a speeding subway train is a little hokey (apparently, most of the effects budget went into vampire stingers, not the slow motion effects)? It's the emotions that matter the most.