Following their father’s death, two sisters, Kana and Anri, are forced to confront one of the most pressing issues troubling much of the modern world, namely who will take care of their ailing mother, Akiko. Confined to a wheelchair and seemingly senile, Akiko requires constant care. In this case, however, the problem initially appears nonexistent, as Kana is willing to assume responsibility from the very beginning.

Soon enough, though, tensions arise within their shared household, and not all of them are of a physical nature. Kana begins experiencing strange dreams and vivid premonitions, one of which involves a high school classmate jumping in front of a train, a vision that soon becomes reality. Kana’s stress levels reach a breaking point, while the classmate’s death marks only the beginning of a series of disturbing events that seem connected to Akiko’s increasingly bizarre behavior and her papier-mâché dolls.

Gradually, Kana becomes convinced that something else has taken over her mother’s body, something her father had also hinted at to a family friend who has remained close to them for years, the psychiatrist Kumagai. He, however, believes Kana is suffering from psychological issues.

From the outset, beginning with the father’s funeral that opens the narrative, Sakai Zenzo establishes an atmosphere of tension, disorientation, and mild hilarity, although the latter element fades rather quickly. This atmosphere persists until the very end, while the first two components steadily intensify and, together with an ever-present sense of unease, carry the story forward in a consistently rewarding manner.

Contextually, the main source of this tension is Kana herself, and the central question of whether she is losing her grip on reality due to a psychiatric condition or whether she is actually correct and something genuinely terrifying and supernatural is unfolding. The answer to this dilemma also shapes the perception of the surrounding characters, determining whether they are sincere helpers, opportunists, or even complicit participants in the strange events. The fact that this ambiguity lingers for a significant portion of the runtime greatly enhances both the oppressive atmosphere and the pervasive sense of creepiness.

This ambiguity is also reflected in the uniformly strong performances. Rio Yamashita stands out in the demanding role of Kana, delivering a layered and convincing portrayal, with her antithesis with the more grounded, Ann Ogawa’s Anri, forms one of the most intriguing axes of the movie. Makita Sports as Kumagai manages to appear both ambiguous and an authoritative figure in the same time, while the rest of the cast effectively embodies the uncertainty that defines their characters.

Keisuke Miyazaki’s editing frequently shifts the tone between horror and drama, with flashbacks that manage both to clarify certain points and to further complicate others. Although the pace remains deliberately slow throughout, it never feels stagnant, and at eighty nine minutes, the narrative never overstays its welcome. Ryotaro Kawaguchi’s cinematography is equally impressive, capturing the unsettling atmosphere in a way that allows shadows to shape the mood, while the gradual shift from bright colors to more desaturated tones proves particularly effective.

Ultimately, “IAI” stands out as an accomplished work on every level, clearly demonstrating how horror can function in contemporary cinema, and emerging as a title that can easily be described as a true gem.