A teenage girl tries to unravel the mysteries of love, sex and attraction in this coming-of-age comedy-drama from Sweden.
Lina (Mylaine Hedreul) is fifteen years old and is tired of not getting much attention from boys, unlike her friends Thea (Alice Kastrup Moller), the pretty popular girl at school, and Carro (Lovisa Onnermark), a gregarious type without a hint of shyness.
Lina suspects the reason her male classmates are avoiding her is they know she's a virgin, and she decides to do something about it. With Thea and Carro's help, Lina sets out to find a boy who would be willing to seduce her, though the field of contenders seems unfortunately narrow.
Lina has long had eyes for Ivar (Viktor Axelsson), a boy in her class, but even though he's cute she also thinks he's thick-headed, not to mention that he once nearly threw up on her during a date.
Elsewhere, Lina is taken with Danne (Rickard Roxvall), who is charming and good-looking; however, he's also a few years older, and she's afraid he may be out of her league. Bitter Sweet Heart was originally released in Sweden as Linas Kvallsbok, which translates as Lina's Diary; it was adapted from a best-selling novel by Emma Hamberg.