_Grimm is at its best when the writers use the fairytales on which the series is based, as a jumping off point rather than a blueprint for the whole story. The weakest episode so far was “Danse Macabre” which attempted a too-literal interpretation of “The Pied Piper of Hamelin” and ended up giving us the slightly ridiculous spectacle of a man playing a violin to bunch of bemused looking rats - surprising, given that the writers were also the originators of the series: David Greenwalt and Jim Kouf. But “Let Your Hair Down” was written by the same pair who penned last week’s far superior “The Three Bad Wolves” and although this latest episode sounds from the title like it’s going to be a reprise of “Rapunzel”, Sarah Goldfinger and Naren Shanka swiftly dispense with the need to stick to the story of the girl locked in a tower. There is a girl, but she’s lost in the woods and her hair isn’t so much an escape route as the way she kills her prey.

This take on the source material dovetails neatly with legends like the Jersey Devil or Big Foot, leading the series more in the direction of The X Files than Buffy, the latter a series Greenwalt worked on as well as Angel where he teamed with Kouf. This may explain their emphasis on the fantasy element, when in fact Grimm works much better as a cop show with beasties thrown in. Because this episode focuses on the case rather than the creatures, Hank gets to do some investigating on his own, giving Russell Hornsby more weight and depth than just acting as Nick’s unwitting sidekick. Hank has to do a lot of ignoring of the obvious, as Grimm creatures scamper around killing each other in ways ordinary human criminals would never think of and Nick comes up with solutions gleaned from his Aunt Marie’s private library, so it’s nice to see the character getting to act like a real cop for a change. It’s also refreshing to see Nick using observation and brain power to work out what happened to the kink-necked corpse (“that’s one broken guy,” remarks Hank), rather than being handed the answer on a plate - usually because the guy he’s interviewing gives himself away by growing a faceful of shag pile carpet.

But we’re not allowed to forget that Nick is a Grimm, as well as a cop. A single line of dialogue from Captain Renard instructing Nick to bring any hard evidence about the girl’s existence straight to him, reminds us that Renard is not just a cop either, but is part of the Grimm world too. And when Grimm creatures stake out Nick’s place and flee in panic on his arrival home, it underlines the point that Grimm’s are executioners, not peacekeepers. Nick tracks down “Rapunzel” with the help of Munro, but instead of dispatching her, makes sure she gets medical help and is returned to her family. A traditionally minded Grimm might see that as a betrayal of their role as creature-slayers so it will be interesting to see if Nick is allowed to continue reinterpreting his ancient calling or if he is pushed to toughen up his act. If he does have to kill rather than police, that’s going to affect his growing friendship with Munro and also challenge Nick’s own perception of himself, always an excellent course for any drama to take.