When Johanne, at 17, writes a memoir about her passion for teacher Johanna, the precocious result rattles three generations

Here is the third in a playful trilogy from Norwegian novelist and film-maker Dag Johan Haugerud (after Sex and Love, which appeared last year at Berlin and Venice respectively). This one is a sly, garrulous, mischievous piece with something of Lukas Moodysson’s early film Show Me Love; it saunters lightly and entertainingly along, breaking all the screenplay-seminar rules against voiceovers (of which it has lengthy stretches but it never feels oppressive). I can imagine two different sorts of US English-language remake: one which ramps up the wry indie comedy, and another which transfers the emphasis to a dead-serious generational family drama. Neither would have this insouciant flavour.

The setting is Oslo and Ella Øverbye plays Johanne, a 17-year-old at high school who is dissatisfied with her life; she lives with single mum Kristin (Ane Dahl Torp) and is also close to her grandmother Karin (Anne Marit Jacobsen). Her world is turned upside–down with the arrival of new teacher Johanna (Selome Emnetu) who is dynamic, charismatic and attractive. Dreamy Johanne nurses a crush on her that escalates to obsession and she becomes deeply in love with this beautiful, inspirational teacher – which plunges her into depression. In desperation, Johanne goes round to see Johanna uninvited, knocks tearfully on her door and Johanna opens it and hugs her, apparently instantly empathetic. Or is there something more? …