Legos were invented in 1949. The character of Batman, 10 years before that. "The Lego Movie" (2014) and this year's "The Lego Batman Movie" riffed brilliantly on those storied histories — simultaneously mocking and honoring pop subcultures that have grown organically around millions of acts of individual imagination spurred on, in the first case, by building blocks, and in the second case, by comic books, TV shows, movies and, eventually, Batman-themed Lego minifigs (or minifigures) and construction sets.

These were movies that could be — and that were — enjoyed by adults as well as children.

"The Lego Ninjago Movie," on the other hand, is based on a line of Lego building sets that debuted — along with a TV series that was little more than glorified commercials for those toys — in 2011. Unlike the first two Lego films, which tapped into widely accessible universes, "Ninjago" demands a familiarity, not with any recognized cultural touchstone, but with a relatively obscure — and prefab — children's plaything.

From left, Kai (voiced by Michael Peña), Nya (Abbi Jacobson), Cole (Fred Armisen), Zane (Zach Woods), Jay (Kumail Nanjiani) and Lloyd (Dave Franco) in “The Lego Ninjago Movie.” (Warner Bros. Pictures/Warner Bros. Pictures)

To be sure, the ninja-themed Ninjago toys, shows and video games are themselves takeoffs on martial-arts movies and such ancillary mythologies as "Teenage Mutant Ninja Turtles," "Power Rangers" and "Xiaolin Showdown." But for anyone without a preexisting interest in and/or familiarity with those adolescent-action-hero sagas, "The Lego Ninjago Movie" presents an obstacle to full and immediate appreciation.

The story, crafted by a raft of six screenwriters and three directors, concerns a posse of high school students who secretly moonlight as crime-fighting ninjas, each of whom is defined by an elemental force — earth, water, lightning, fire and ice — and a colored uniform: black, gray, blue, red and white. A sixth and green ninja, Lloyd (voice of Dave Franco) has the added burden of being the estranged son of the crew's archenemy, Garmadon (Justin Theroux), a four-armed warlord intent on the destruction/domination of the land of Ninjago, a Japan-esque nation constructed from Lego building blocks and populated, paradoxically, by non-Japanese minifigs.

Lessons will be learned about teamwork and reconciliation, and many jokes will be told along the way.

An ordinary house cat is dubbed “Meowthra” in the film. (Warner Bros. Pictures/Warner Bros. Pictures)

Master Wu is voiced by Jackie Chan. (Warner Bros. Pictures/Warner Bros. Pictures)

Garmadon, center, is voiced by Justin Theroux. (Warner Bros. Pictures/Warner Bros. Pictures)

Some of those jokes are pretty funny, and include such clever touches as Ninjago being terrorized by an ordinary house cat (dubbed Meowthra, in a nod to the deliciously cheesy movie monsters of the Japanese studio Toho, home of "Mothra" and "Godzilla"). Meowthra's destructive rampage is triggered when Lloyd unwisely gets his hands on something called the Ultimate Weapon, which turns out to be just a laser pointer.

Such cheeky self-awareness runs throughout the film, giving it a mildly fizzy meta-charge, as when one of the ninjas refers to the "needlessly cryptic metaphors" of their sensei, an ancient ninja master (and Garmadon's brother), played by martial-arts star Jackie Chan.

But more often, "The Lego Ninjago Movie" feels like it's obeying the conventions of throwaway entertainment when it should be making more of an effort to comment on it. When the ninjas — voiced by Fred Armisen, Kumail Nanjiani, Abbi Jacobson, Michael Peña and, in the role of a cybernetic "nindroid," Zach Woods — mount their Transformer-like robotic vehicles, or "mechs," to fight Garmadon, the film turns into a noisy, visually busy and unengaging iteration of a Saturday morning cartoon, rendered in Legos.

The question is: Who is this movie for? The Lego-branded toys and TV show that inspired it are far from educational, but for viewers who don't know — or care — about them, there's too steep a learning curve for "Lego Ninjago" audiences to have as much fun here as Lego would like.

PG. At area theaters. Contains mild action and rude humor. 101 minutes.