When the promo showed “South Park” would be taking on freemium games it felt a little like pointing a bazooka at a barn owl, but Wed. night’s episode of “South Park” had something that has been in short supply for the show: righteous anger. The targets of “South Park” scorn have begun to feel almost obligatory.

There are certain must-target targets destined to get the “South Park” spin. Of course “South Park” must address Trayvon Martin, or the election, or the NSA. But the more Matt and Trey sicced the boys on high profile targets, the more it felt like “South Park” didn’t have a real position, often settling into a default contempt for all sides. And while it feels weird evaluating a show the same way you would an undergrad English paper, the best “South Park” episodes are often those with a coherent thesis and a defined stance. That clarity of purpose made this most recent episode of “South Park,” “Freemium Isn’t Free,” the best of the season so far.

'South Park' Season 18 Episode Review

The episode opens on Jimmy peddling a Terrance & Phillip freemium game to Stan. While the boys see through the veneer of gameplay to the underlying wallet vacuum, something grabs Stan and he soon finds himself spending thousands of dollars purchasing Canadough, fueling an addiction that can only be defended by self-delusion obvious to his friends. Meanwhile the Canadian Minister of Mobile Games strings along Terrance and Phillip, who object to the sleazy properties of the game but just can’t help taking all that money, pal.

It is here, in the Canadian government offices, that we find “South Park” at its most preachy, laying out on whiteboards the insidious psychological trick at the heart of freemium, and the particular weaknesses it seeks to exploit in natural addicts like Stan (though it seems Stan has kicked the alcoholism developed after he turned 10). Like the history lessons of the Mormon episode or the lectures guiding Stan through the hallowed secrets of Scientology, this is “South Park” at its most didactic, and probably it’s most divisive. I happened to find it hilarious, but your traction may vary.

Soon enough the true mastermind behind the Canadian freemium games is unmasked, Beelzeboot, Satan’s Canadian brother. Like everything in Canada (and this episode has a Canada enriched by the fleshed out mythology provided by “South Park: Stick of Truth”), Beezleboot is hilarious. “South Park” has set a new low for how chunky and awkward they can get their animation (after years of the show becoming more smooth and expressive), as Beelzeboot flies around the Canadian Ministry dropping long flaming turds in his wake, his square head flopping with laughter. Beelzeboot is probably the best new character “South Park” has added since the arrival of the new cops in “The Jeffersons.”

Soon enough Satan is explaining addiction to Stan in concrete terms, setting him down on the bed to explain all about genetic factors and dopamine imbalances, before flying off in Stan’s possessed body (“can I borrow your soul for a minute?”) to fight Beelzeboot over his unsubtle freemium manipulations. The scene with Satan essentially demystifying addiction really lays it all bare. It’s a scene with genuine sentiment, that sheds light on the ways in which we problematize our own behavior, looking for answers in all the wrong places.

Like “A Scause for Applause,” which targeted Lance Armstrong and a culture of hollow wristband support, the fury over something so trivial, but indeed, so insidious, becomes the fuel for everything to follow, rocketing the episode forward and generating humor organically as their well-plumbed characters react. I know I’ve made the new episode of “South Park,” “Freemium Isn’t Free,” sound like a chore, but it’s anything but, with a focused humor driving toward a climactic bit of well-earned absurdity missing from more unfocused efforts from this, Season 18 of “South Park,” like “Gluten Free Ebola.”

Check out the latest episode of “South Park,” “Freemium Isn’t Free” while it’s still available for viewing on South Park Studios, before it falls behind that new Hulu paywall.