Present day Finland. Some members of the Kurtti family travel to Kos on holiday, but all remember a tragedy 12 years previously. Grandfather Risto receives a letter he believes is linked to that event.
In 2019, twelve years after the tragic death of his grandson Tommi, Risto Kurtti receives a mysterious letter at his home in Helsinki. In 2007, the family arrives for Midsummer celebrations down by the lake - much to the interest of local boy Elias Leppo.