The best friends of Kacper and Emma are going on vacation with Emma's grandfather Jørgen at the seaside. They use baths, collect shells, build sand castles, fly kites and even fish. Holidays like any other time, until they find a mysterious chest on the beach. It is a time capsule with a souvenir of the past and a map. An exciting adventure begins for Kacper and Emma. In the meantime, they will learn more about the people living on the island and how they lived there in the past.