Whoever Steals This Book is a film filled to the brim with imagination. Mifuyu's adventure takes her into wonderfully realized storybook worlds. There's a Japanese fairy tale filled with surreal visuals, a noir detective story portrayed with a black and white color palette and film grain over the top, and a dystopian sci-fi world that mixes grit and grime with sleek futuristic design and fantastical monsters. The visual style for the film is simply excellent from start to finish. You can tell that the people animating the film put their heart and soul into it, while having more than a bit of fun as well.

However, Whoever Steals This Book is, unfortunately, one of those films that is 100% style over substance. Now, that's not to say that the movie is incomprehensible. Rather, it's the opposite: The problem is that the film is painfully surface-level. It's the adventure it purports itself to be and nothing more. There is no greater meaning or message it wants to pass on to its audience. There is no social commentary, nor is the audience challenged to re-evaluate deep-rooted core values or think about a key aspect of human nature.

The storybook worlds Mifuyu visits, while excellently animated, have basically no impact on her as a character. While this is ultimately the story of her overcoming past trauma, this aspect only comes to the foreground in the final act of the film when her repressed memories come flooding back. Worse still, each of the three fictional worlds is cliché to the extreme, to the point that each feels like a half-baked caricature rather than an actual attempt to invoke their respective genres.

Likewise, while each world is populated by familiar faces playing new roles within each fictional world, nothing is done with this. It doesn't even teach us more about the townspeople in Mifuyu's real world. It's just the same character designs with the same voices playing different characters—like having the same actors across different films or plays.

More than anything, Whoever Steals This Book feels like it could have been—should have been—more than it is. Each world could have taught Mifuyu something about herself—helped her mature and prepare for the final climax where she confronts her past trauma. They could have helped her better understand the people of her town with each corresponding character acting as a living metaphor—highlighting one aspect or another of each character's more complex personalities. However, none of this is even attempted.

When it comes down to it, Whoever Steals This Book is a straightforward fantasy adventure to be watched once and forgotten about. It's a movie to put on for the kids while you do something else. The visuals are above average, and the creativity on display is certainly heartfelt, but that's simply not enough to make it stand out against the anime films of this past year, much less the anime greats. It has all the pieces to have been something more, but it ends up feeling like a wasted opportunity when all is said and done.