Never before has a stamp collection led to a game like this - a dangerous game. Do you dare to join Paula, our young protagonist, in this adventure that will change her life? The novel takes place in Barcelona where Paula, a 14-year-old teenager, lives. One day when she goes to visit her grandfather Fermín, she finds him dead, hanging from the awning of the terrace. Paula does not believe that he has committed suicide and, investigating what might have happened, she discovers that her grandfather owned a priceless stamp: The seven-masted schooner. It now belongs to Paula. But this happy news soon turns into a nightmare because there is too much money at stake, and some very dangerous people prepared to kill to get their hands on it...