The legendary man of science from Wroclaw, her daughter and his unusual and mysterious invention

Six-year-old Bi has been afraid of water since the flood took her younger brother. Her father, Karl Klingert, dedicated himself to working on the world's first diving suit. Bi thinks the suit is the monster that took over her father. With the help of Peter, a young bully from the river, she tries to destroy it before the whole family leaves Wroclaw forever.