Twelve-year-old Zac sets out on his first solo mission as a spy for the Government Investigation Bureau, piloting an amphibious submersible in hopes of preventing enemies from accessing a top-secret transmitter 4,000 feet below the ocean's surface.

While Gwin, a Fetcher, and her family defy the Devouts by sharing song and story, the Oyster's crew and the Sunkers continue fighting to bring light back to the dark world.

"Climb aboard Alvin, the famous deep-sea submersible credited with helping to find the Titanic, and take a trip two miles down to the bottom of the ocean. Experience a day in the life of an Alvin pilot and join scientists at the seafloor to collect samples and conduct research. Along the way, discover what one wears, eats, and talks about during a typical eight-hour trip in a underwater craft and find out more about the animals that live deep in...

Building a submarine without the resources of a big shipyard and using only scavenged or off-the-shelf parts is an unusual idea by any standard. But Peter Robbins has dreamed of submarines all his life, and he is an unusually determined man.

"In the spirit of Bill Bryson and Ian Frazier comes this fascinating examination of our past, present, and future beneath the waves. In an age of unprecedented exploration and innovation, our oceans remain largely unknown, and endlessly fascinating: full of mystery, danger, beauty, and inspiration. Bill Streever--a longtime deep-sea diver himself--has masterfully woven together the science and history of Earth's last remaining frontier: the sea. In...