ChaO Review (2025 BFI London Film Festival)

Love is a peculiar thing. We do not choose whom we fall in love with; it’s a spontaneous emotion we experience. That spontaneity is precisely what makes it so complicated. Love can be one-sided, it can deteriorate over time, or it can blossom into a lasting relationship. ChaO, the latest film from the Imaginative Studio 4°C, is a playful twist on a fairytale love story, revealing that what’s written in books is often simpler than reality. It explores the romance between a human and a mermaid, showing that love is rarely as simple or conventional as it appears on the surface.

Set in a future Shanghai not too different from our present, humans and mermaids are locked in a dispute, and negotiations are stalling. The mermaids demand that humans abandon boat propellers, as they seriously injure sea life if caught up in their force. A junior designer at the city’s leading shipbuilding company, Stephan (Oji Suzuka), may hold the key to resolving the conflict, but his boss doesn’t respect him and instead assigns him to clean the company’s newest vessel. While scrubbing the deck, Stephan is nearly devoured by a mermaid that leaps from the sea. After the incident, Stephan wakes up in the hospital and learns that the mermaid is actually the princess of the merfolk called ChaO (Anna Yamada), and she has chosen him to be her fiancé.

Studio 4°C has always been a revolutionary force within Japanese animation, with their early works like Mind Game, Tekkonkinkreet, and their contributions to The Animatrix cementing their reputation for boundary-pushing visuals. ChaO, in many ways, feels like an artistic love letter, a culmination of the studio’s previous work. It fuses the surreal character designs and urban sprawl of Tekkonkinkreet, the kinetic action of The Animatrix, and the fluid, mesmerising water animation of Children of the Sea. While the quality of their narratives has varied over time, one constant remains: their visuals are consistently transcendent. ChaO is no exception.

The film opens with a fairytale paper-drawing aesthetic before transitioning into a brightly coloured, water-infused vision of Shanghai. The real-life city is undeniably picturesque, and that quality is beautifully captured here. Characters are designed with sheer abandon for convention; Stephen’s boss resembles Humpty Dumpty more than a human, and ChaO, in her mermaid form, evokes an evolved manatee. This bold stylisation lends the film a wholly unique identity. The colour palette is vivid yet warm, radiating a comforting atmosphere. Even the title drop feels special, executed with a level of animation that borders on perfection.

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Stephan, as our protagonist, is where the film falters greatly. While not unlikeable, his agency in the plot feels neutered, as for the majority of the film’s runtime, he doesn’t want to marry the mermaid and instead wants to develop his air system for ships. Beyond that, it is not until we approach the ending that his connection with ChaO is revealed that we understand and fully bond with the relationship. ChaO, on the other hand, is an utter delight, while her acceptance of gender roles can be viewed as problematic. I adored seeing how this mermaid learns to adapt to the human realm and love Stephan for who he is, flaws and all.

Stephan and ChaO’s relationship can be interpreted through an LGBTQ+ lens, as a deconstruction of gender and a reminder that love transcends identity. We can love people for who they are, not simply for their gender. While I feel the film could have explored this thematic thread more deeply, especially since ChaO, despite being a mermaid, is still identified as a woman and, in her more human-like form, appears conventionally attractive, it nonetheless gestures in a progressive direction.

While not a major distraction, the framing device through which we witness ChaO’s events occasionally undercuts the tension. Yet as the story nears its conclusion, I couldn’t help but become emotional. Watching Stephen fight to reclaim ChaO’s love in a colossal kaiju battle at sea is both visually breathtaking and narratively resonant. This final set piece is elevated by the film’s score, which, across its brisk runtime, is a consistent auditory delight.

ChaO has its flaws, but every narrative thread is neatly sewn together by the time the credits roll. I couldn’t help but get swept up in this beautiful tale of long-lost lovers and unconventional romance: it is a feast for the eyes and an absolute blast.

★★★★

Screening as part of the 2025 BFI London Film Festival on October 11th and 13th / Screening as part of Scotland Loves Anime 2025 / Oji Suzuka, Anna Yamada, Shunsei Ôta, Kenta Miyake, Kavka Shishido / Dir: Yasuhiro Aoki

About the Author

Robert Ewing

Author

Rob is a freelance film critic and writer who specialises in Anime and Asian cinema. I have adored film since a young age, having watched films that were far too old for me, such as RoboCop, Die Hard, and Hot Tub Time Machine, to discovering the heights of foreign cinema through films like Headhunters and Battle Royale. Growing up with such a diverse catalogue of films that I cherished sparked my desire to discuss them. This passion eventually led me to become a reviewer. Dissecting films, speaking to filmmakers I admire, and showcasing the best of Asian and anime cinema is how I live my best and truest life.

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