So here we are, finally, at Psycho. One of the things that has made Bates Motel so good through the years is how it puts its own spin on the world Alfred Hitchcock created on screen from Robert Bloch’s novel. The touchstones are familiar (the motel, the mother / son relationship, a slow buildup to the killings), but the way the show has explored the relationship between Norma (Vera Farmiga) and Norman (Freddie Highmore) has not only been unique, but at times enthralling.

The blessing and curse of a show that designs itself as a prequel is that it will eventually have to catch up to the source material. Though there is some excitement found in the expectation of what is to come, it also reduces the stakes. We know, to a certain degree, how things are going to end up, especially if the worlds are directly connected (think Better Call Saul in relation to Breaking Bad). But Bates Motel is set in a different time, and was clear from the beginning that its story would be wholly its own. With “Marion,” Bates doubled-down on that, changing up the iconic shower scene in a way that was smart and also necessary.

First there’s the obvious thing: you’re not going to be able to go up against Hitchcock’s direction in one of the most famous scenes in cinema history and win. The show putting its own spin on the moment was not only a clever twist, but a moment that was wisely self-aware. For weeks now we’ve watched the Marion Crane (Rihanna) storyline develop, as she carries on (unknowingly) an affair with Sam, steals the money from her employer (putting us in novel/movie territory), and arrives at the Bates Motel one dark and stormy night. She doesn’t hear Norman arguing with his mother like we do, yet much of the rest is the same — he offers her something to eat, explains about the taxidermy, and she takes a shower while he watches.

There’s a certain suspense here even though we think we know what’s going to happen: Norma will goad Norman, and then Mother will kill Marion. But that suspense triples when Marion exits the shower and wants to go after Sam, asking for Norman’s help. From there, we become unstuck within the story. Will Marion return to the Bates Motel? Is the inevitable just being drawn out? Yes and no; Marion returns, but Norman (who himself is finally self-aware when it comes to the reality of “Mother”) sends her away, saving her from Mother’s wrath. But her influence has nevertheless been activated, so it’s the feckless Sam who ends up being murdered by Norman in the shower.

Phil Abraham, who directed “Marion,” left the thematic touchstones of Psycho’s shower scene intact without remaking them. There are some differences in the story, anyway: Norman isn’t blacked out, he’s choosing to kill Sam after Mother goads him. Sam sees him fully, and there’s no sharp string accompaniment that hits with every knife plunge. There doesn’t need to be — that version exists, and if we’ve learned anything over the years with Bates Motel is that it is in a tangential universe to Psycho. It uses just as much of the story as it needs, but its own world is so rich (especially with Farmiga and Highmore’s performances) that it can also take things in a slightly different direction — like with “Marion” — and it still work.

As Bates Motel has made the turn into its final two seasons, it has been able to focus back on its core theme, which is Norman’s transformation into a killer. Though Norman has killed throughout the show, the journey has been in him first even remembering the murders, then thinking that Norma committed them, and now realizing that it is him, under the thrall of his “Mother” creation. While other parts of the show (mainly the White Pine Bay subplots) haven’t always been as successful, watching Norman fully realize his capacity as a killer, and having those around him realize it as well, has been a moody and often surprisingly emotional journey (surprising only because we knew it was coming). Now that Dylan and Emma are getting pulled back into Norman’s world, and Romero is somewhere still on the hunt for him, a series of intense showdowns seem imminent. And yet, after “Marion,” we can no longer predict how it all might go down. That is a wonderfully spooky thing.