Occasionally two networks each debut a show with basically the same premise. Remember "30 Rock" and the short-lived "Studio 60 on the Sunset Strip"?

Occasionally two networks each debut a show with basically the same premise. Remember “30 Rock” and the short-lived “Studio 60 on the Sunset Strip”?

Apparently, ABC and NBC both thought modernizing the fairy tale genre was a good idea.

ABC’s “Once Upon a Time” has a yarn where the Evil Queen (Lana Parrilla) casts a spell that sends her, Snow White (Ginnifer Goodwin), Prince Charming (Josh Dallas) and other fairy tale characters to present-day Storybrooke (see what they did there?), Maine.

Created by “Lost” writer Adam Horowitz, “Once” is similarly about people being trapped somewhere while using flashbacks to tell their backstory.

In Storybrooke no one remembers their origins — except for the queen, who’s now the mayor — and they live ho-hum lives.

A precocious boy named Henry (Jared Gilmore from “Man Men”), who’s been adopted by the Evil Queen, decides to fix all this by tracking down his real mother, Emma Swan (Jennifer Morrison), who’s the daughter of Snow White and Prince Charming. Henry believes Emma is the only one who can reverse the queen’s spell.

While “Once” is somewhat convoluted and bounces between settings, NBC’s “Grimm” is a pretty straightforward cop drama, with a twist.

Two cops are investigating a gruesome murder when Det. Nick Burkhardt’s (David Giuntoli) mysterious aunt shows up and reveals that her family members are Grimms — people who see the true nature of demons, wolves and evil doers and are charged with fighting them.

Of course the case Nick and his partner Hank (Russell Hornsby) are working on turns out to involve a beast from the Grimm fairy tales.

While “Once” contains the stronger mythology and far superior cast, “Grimm” feels mostly like a procedural, with Nick figuring out the family’s history on the side.

Still, I actually like “Grimm” a little better, which is damning with faint praise. “Once” is too sappy and soapy, and the fairy tale flashbacks — which should be fun — are kind of boring. It also feels like “Once” should be a mini-series; its serialized aspects could get repetitive down the line.

As much as I like Goodwin, Morrison and Robert Carlyle as Rumpelstiltskin, “Grimm” bests “Once” by being more playful, occasionally dark and more faithful to its source material.