My grandmother is a pirate! The secret of grandmother's chest

The heroines of this book are not the grandmothers who knit socks, bake pancakes, or gossip while sitting on benches. One of them is a real pirate; she sails the seas and oceans and has dedicated her life to treasure hunting. You will learn about her in the story "My grandmother is a pirate!". And the second one... Almost nothing is known about the second one ("The secret of grandmother's chest"), but distant rumors have reached Romka and his friends—the heroes of the story. Now the boys will have to uncover the mystery of the abandoned house and the chest discovered in the old attic. They will have to risk their lives more than once: visit the bottom of the sea, hide in a maze from a monster, and fight with monsters.