Until the early 1870s, very little was known about the creatures lurking in the depths of our oceans. People had found a few things trapped in fishing gear, but those who tried to venture to the bottom of the seafloor often died before they made it there. The first systematic investigation into life in our oceans was made during the circumnavigation of the HMS Challenger. Scientists credit this voyage as the beginning of modern oceanography, and the story of it is full of twists and turns. In this book, Graham Bell takes listeners through the voyage station by station, following the progress of the expedition and introducing some of the new and strange animals that were hauled up from the depths of the ocean and seen by human eyes for the first time.

The book begins with a description of the first attempts scientists made to explore the deep sea, leading up to the plan for a voyage around the world on the HMS Challenger. Bell details what was discovered during hundreds of stops to take samples, and he describes around a hundred stations where remarkable animals were hauled from the sea. The book ends with a description of what came after the end of this journey, explaining what they did with the animals that were collected and what became of the scientists and sailors who planned the voyage and traveled together around the world.