 Billy expects his summer to be boring, but with the German U-boats endangering the maritime coast, his work with Bell's hydrofoil becomes an adventure.This book is often chosen by teachers in Ontario, Canada as part of the ESL, Level C curriculum.The book is set during the first World War and although it is a work of fiction, it serves as a launching pad for discussions about Canada's involvement in the war and the contributions of Canada's leading scientist, Alexander Graham Bell.