For decades, the world has been dreaming of a way for Pokémon and humans to co-exist. The idea of catching "pocket monsters" as companions has held society's attention since kids first hunched over Game Boys in the late 1990s, taking on the Herculean effort to catch 'em all. The Pokémon Company has made strides in recent years to make that fantasy more of a reality, specifically with the Pokémon Go augmented reality mobile game released in 2016. Now, Detective Pikachu takes that idea further, creating a world where humans and creatures exist in pure harmony through a story where heart trumps actual mystery.

Rather than set the story in any of the games' regions, the film takes us to Ryme City, a bustling, glistening metropolis. While '90s kids who were obsessed with the original 151 Pokémon will get their fill thanks to abundant Generation 1 cameos (including an appearance from original movie villain Mewtwo), chronic trainer and ageless anime mainstay Ash Ketchum is nowhere to be found. Instead, we get Tim Goodman (a clouded, yet grounded Justice Smith), a former trainer brought to the city by the disappearance of his estranged father, Harry. Navigating his dad's empty apartment, Tim discovers the room his father had set up for him, a representation of how much the past irreparably severed their connection.

Then, he finds a talking, yellow rat, aka, the titular Detective Pikachu.

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Much like the game of the same name, Detective Pikachu focuses on the partnership between Tim and Pikachu, Harry's partner Pokémon, as they work to discover the real story behind his mysterious disappearance. Their investigation takes them all over Ryme City, a journey where the film shines brightest. Director Rob Letterman has built a world where Pokémon walk unencumbered next to their humans like a best friend. Rufflets and Aipoms are as common as pigeons and sewer rats, and Gurdurrs and Machamps work side-by-side with construction workers, building a better future for humans and Pokémon alike.

Detective Pikachu

Though these creatures are shown to be extremely capable, their speech patterns fall into the franchise adage of only saying their own names. Pikachu is the exception, able to speak directly to Tim with the voice of Ryan Reynolds. While it is a tad disappointing not to hear Danny DeVito's gruff take on the conducting rodent, given the Internet's obsession with him playing the part, Reynolds' vim and vigor are, in a word, electric. He speaks in a sly and energetic patter, using every breath in his grape-sized lungs to keep up with his overly-caffeinated thought patterns. Pikachu considers himself a hard-boiled detective from the salad days of noir, and Reynolds' performance ends up equal parts Deadpool and Sam Spade. His facial reactions also manifest in the impressive visual effects, as the film succeeds in the illusion of his existence, down to subtle changes in his fur.

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If only that infectious enthusiasm made its way into the mystery itself. Though the search for Harry provides many unexpected twists and turns, especially in the film's final act, Detective Pikachu tends to go for style over substance. Tim is not the only human player in this mystery; he's accompanied by plucky upstart journalist Lucy (Big Little Lies' Kathryn Newton), challenged by hardened police officer Hide Yoshida (an always game Ken Watanabe), and tied into the plight of father/son business magnates Howard (Bill Nighy) and Roger Clifford (You're the Worst's Chris Geere, channeling a media-savvy Veruca Salt). The biggest highlights are all Pokémon-centric, ranging from a glance into the world of real-time battling to a hilarious pantomimed interrogation of an informant Mr. Mime.

What makes the story interesting isn't the plot, especially when it veers into the tropes of secretive scientific projects. It's the idea that The Maltese Falcon could be done with actual Talonflames, bringing unusual creatures of all shapes and sizes into conventional narratives and themes. At its heart, the film is about companionship, in all sense of the word. Characters struggle with their relationships to humans and Pokémon alike, as the film illustrates how much the help and heart of another can make one evolve into the best version of oneself, both literally and metaphorically.

At one point, Lucy speaks with Tim about how communicating with a partner Pokémon is more about feelings than words. Perhaps that is the best way to take in this film, ultimately. While the writing provides some genuine surprises and resolutions, it is far from a game-changing mystery story. Instead, what should be remembered are the emotions behind each word, whether spoken English or Pokémon. With a wonderfully creative setting and resounding themes, Detective Pikachu works past its weaker writing to remind children and adults alike of the world of possibilities that come with an open Pokéball.

Directed by Rob Letterman from a script written by Dan Hernandez and Benji Samit, Detective Pikachu stars Justice Smith, Kathryn Newton, Ken Watanabe and the voice of Ryan Reynolds. The film opens in theaters on May 10.