A troubled young boy, Oskar, is trying to cope with the loss of his father. Oskar starts lashing out at his mother and the world. Until a year later, he discovers a mysterious key in his father's belongings and embarks on a scavenger hunt to find the matching lock, just as he used to when his father was alive. On this journey he is bound to meet a lot of people and learn a lot about himself and his family, but will he ever find the lock?