A coda to a hugely popular manga and anime series, Fruits Basket: Prelude steps away from the supernatural elements of its preceding iterations while aiming to retain their emotional lyricism. The first half-hour of this “prelude” functions as a recap of the series; this lengthy prologue revisits how Tohru Honda, a sensitive orphaned girl, falls in love with Kyo, a teenage boy who is cursed to transform into a cat when touched by a member of the opposite sex. These events, absorbing enough when told over the course of the series, are a bit of a slog when conjured up in this clipped format. Simply checking off the high points of their relationship is going to be confusing for newcomers and all too familiar for ardent fans.

But when Fruits Basket: Prelude finally kicks off its narrative thread, which follows the life of Tohru’s mother Kyoko, who dies in a car accident, becomes serviceably engrossing. The romantic elements might raise some eyebrows – Kyoko and Tohru’s father meet as student and teacher in a junior high school – but Kyoko’s transformation from a lost delinquent to a doting mother is rather movingly done.

Still, considering that Kyoko’s story only takes up about two-thirds of the running time, the whole enterprise feels like careless fan service. The decision to split Tohru and Kyoko’s struggles into parallel lines is an odd one, and a missed opportunity. Considering the way Kyoko faces abuse and neglect from her own parents, Fruits Basket: Prelude could have probed further into how intergenerational trauma informs Tohru’s own identity now that she is building a family with Kyo. All in all, this is a film that will not only fail to convert new believers but also frustrate the existing fanbase.

• Fruits Basket: Prelude is released on 20 July in cinemas.