15 - Tom Swift and the Electronic Hydrolung by Victor Appleton

When a top-secret space probe is mysteriously shot down over the ocean, Tom Swift Jr. jumps into action with his latest invention—the Electronic Hydrolung! In Tom Swift and the Electronic Hydrolung, the young genius must race against a shadowy enemy to recover the probe from the ocean floor before it falls into the wrong hands. With danger lurking beneath the waves and sabotage at every turn, Tom’s ingenuity is pushed to the limit in this thrilling sci-fi adventure.