Hela, the evil sister of the movie’s God-of-Thunder hero, Thor, wants to take over the celestial realm of Asgard, stepping into the power vacuum created by the absence of their father, who, as the movie opens, appears to have been exiled to a senior-living facility on Midgard, aka Earth.

Doctor Strange makes a brief crossover appearance to help Thor find his father.

In one funny sequence early on, Thor witnesses an Asgardian stage play featuring costumed actors portraying him, Odin and Thor’s adopted brother, Loki.

The real Thor, for his part, means to put a stop to Hela’s ambitions, while the real Loki, must decide whose side he’s going to fight on – other than his own, as is his opportunistic habit.

That’s the internecine setup, in a nutshell: Thor, like Abraham Lincoln before him, must put together a team of rivals to take out Hela, who has used her powers to reanimate Asgard’s dead warriors, long laid to rest.

Waititi, a New Zealand actor and filmmaker known for such small, irreverent, indie charmers as “What We Do in the Shadows,” brings exactly the right balance of meaty action and sauciness to “Ragnarok,” which, although big, avoids the bloated, cartoon-noir ponderousness that has, until “Wonder Woman,” plagued movies from the film arm of Marvel’s rival, DC Comics.

“Everything always seems to work out,” Thor reminds us – blithely – not just once, but twice, in a screenplay that elevates “Ragnarok” to the giddy heights of “Guardians of the Galaxy” and “Deadpool” in its refusal to take itself seriously.

Much of the humor is sublimely silly, as in a scene in which Thor tries to explain to Korg how his magical hammer, Mjolnir, enables him to fly.

At another point, Thor learns that the only way back to Asgard from Sakaar is through an interdimensional portal called the Devil’s Anus.