Sven (Lars Eidinger) is a stage actor suffering from cancer who is desperate to perform again. His twin sister, Lisa (Nina Hoss), takes care of him and is equally invested in ensuring that he gets the chance to do so, convinced it would benefit his health and give him something to aim towards. A playwright herself, Lisa's career has stalled and she has followed her husband Martin (Jens Albinus) to Switzerland, where he has a teaching job at a prestigious international school. Her attempts to juggle Sven's welfare with her life become increasingly fraught and, coupled with some personal issues with Martin, it all begins to take its toll on her. Meanwhile, Sven's condition fluctuates massively and his determination to perform once more brings its own conflicts and challenges to navigate.

Directors Stéphanie Chuat and Véronique Reymond bring a light touch to the narrative, and the filmmaking never takes centre stage. This is a good thing, as the film doesn't stylise Sven's suffering, or seek to find a way to make every scene as mawkish as possible. In fact, it resists the temptation to aim for that tearjerker status, and the emotions that the film elicits feel more well-earned as a result. They come as a result of a connection with the characters and the story being told, more than any deliberate attempt to force a response out of the audience.

The performances have to take a lot of credit for when the film achieves this most successfully, as such an approach makes believable acting even more necessary than normal. Hoss and Eidinger are both exceptional and their chemistry and relationship is self-evident; it's obvious that they are twins from the first moment the film allows the viewer to see them together. As such, the honesty of their interplay, and the interplay with their mother Kathy (Marthe Keller) is the film at its best and most valuable. Keller plays off the siblings very well, and the story could easily have spent more time with just the three of them and explored their relationship in further detail.

As it is, the narrative hits a lot of familiar points, and as it reaches its conclusion it becomes clear that while it has generated a connection with the characters, there's something about the familiar ground that it treads that lessens some of the film's impact. Hoss is in incredible form here and she does a fantastic job of selling everything, but My Little Sister doesn't quite take enough advantage of that acting quality to take its impact from moderately affecting with the odd exceptional scene to something that hangs together as a deeply emotional piece throughout. Ultimately, that means it isn't quite as memorable as it perhaps could be, but My Little Sister is still a valuable and engaging film that serves as a showcase for its cast's ability.

My Little Sister is in UK cinemas now