As the 2010s roll over into the 2020s, the fantasy landscape, currently dominated by stories of superheroes and magic, only gets wilder. But imaginary worlds do not begin or end with elves and dragons, something Nintendo and Game Freak are intent on proving with this weekend’s big-screen premiere of “Pokémon: Detective Pikachu.” The film is a love letter to the decades-old video game franchise — and it is not for Poké-novices. In fact, "Detective Pikachu" is extraordinarily strange. Nominally aimed at families, the film combines elements of Ryan Reynold’s “Deadpool” humor, film noir and a meticulously crafted and deeply layered fantasy world, with nary a signpost to explain itself to the uninitiated. That the film is mostly watchable — and even enjoyable on some levels — is a minor miracle.

For those who’ve only ever been vaguely aware of the Pokémon phenomenon, it originally started back in 1996 as a popular Nintendo Game Boy game. The pixelated creation, whose name is a loose take on the Japanese phrase “pocket monsters,” was part virtual stamp collecting (catch all 151 creatures for your collection) and part battle (train your Pokémon to fight). The game’s popularity in Japan spawned a Nintendo console game for TV, trading cards, manga and an anime series, the last of which found its way to American television.

The film is a love letter to the decades-old video game franchise — and it is not for Poké-novices.

By then the brand had firmly consolidated behind the Pikachu mascot, a little yellow electrified furball with an unusual personality. Whereas other Pokémon remained obediently within their masters’ “pokéballs,” Pikachu is far less well behaved and insists on “following” the trainer around the screen like a pet. The character has also starred in his own set of spinoff games, one of which features him solving crimes in the deerstalker hat made famous by Sherlock Holmes.

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Technically, this is all the backstory one needs before seeing “Pokémon: Detective Pikachu.” But in practice, it is not so simple. Not that the movie's plot isn’t straightforward. The lead role of Tim Goodman, played by Justice Smith, is an uncomplicated version of a 20-something young man suddenly dealing with standard daddy issues. Having spent his life in a small town, Tim travels to Ryme City to put his late father’s affairs in order after learning the elder Detective Goodman died in a fiery crash. Upon arriving, and despite what his father’s coworkers tell him, he learns the crash may have been attempted murder — and his father could have survived.

But Ryme City is no ordinary urban landscape. Here, Pokémon and humans live in harmony as equal members of society. Sort of. In practice, humans and Pokémon pair up, sharing a sort of psychic link. Goodman winds up paired with Detective Pikachu, who was his father’s Pokémon partner/crime fighting assistant. More mysteriously, Tim is the only person in the world who can understand the creature’s language. (Everyone else just hears “Pika Pika!”)

And boy, does Pikachu talk. Voiced by Ryan Reynolds, and thankfully not nearly as foulmouthed as Reynolds’ “Deadpool” character, the cute little mascot has a lot of opinions about this world, humans and the ridiculousness of the situation he and Tim suddenly find themselves stuck in. Tim spends most of the film playing straight man to Pikachu’s raging attitude, fueled by more cups of coffee than any mouse-sized creature should drink as they race around the city trying to solve the mystery of who (if anyone) killed Tim’s dad.

And this is where the film stops being a simple video game mystery and goes hog wild.

And this is where the film stops being a simple video game mystery and goes hog wild. Taking a cue from the extraordinarily popular “Pokémon Go” video game, Ryme City looks and feels like augmented reality. Imagine walking past groups of Jigglypuffs heading out to brunch or having to navigate around an enormous Snorlax who has fallen asleep on the street corner. Many-armed Machamps direct traffic, Squirtles are part of the fire fighting brigade and the Loudreds help pump up the jams at the clubs.

If those last two sentences feel like jibberish, then I’ve properly conveyed the sensation one has when watching this film without a full understanding of the universe. No one explains why there is a huge but adorable two-story monster asleep in the middle of the median strip, or why there are funny looking blue turtles walking around and spitting water from their mouths.

That’s not to say the film is not without entertainment value. The human cast is campily hilarious. Kathryn Newton is the “CNM” intern who recognizes the Murdoch-like family she’s working for has been hiding some pretty shady secrets. Bill Nighy is clearly having the time of his life as the Rupert Murdoch stand-in who claims all he wants is equality for all living creatures. And Ken Watanabe brings great gravitas to Detective Hideo Yoshida, the best friend of Tim’s late father, even when he’s doing nothing more than stroking the fur of his loyal Snubbull.

“Pokémon: Detective Pikachu” works far better than one would expect, and includes both laugh-out-loud moments and a few emotionally affecting scenes. But unless you are deeply familiar with the ways of pocket monsters, prepare to be slightly overwhelmed by this zany version of the Poké-verse.