An awe-inspiring, deep-sea-themed picture book that explores the mysterious marine life that dwells within and below the waves, all the way to the very bottom of the ocean!Dive into this compelling, content-rich nonfiction picture book and find yourself on an underwater adventure: a marine mission that takes you past reefs, beyond the near-shore sea floor, down, down, down through the sunlight layer, the twilight layer, the midnight zone—all the way (as in seven miles!) down to the bottom of the ocean!Keep your eyes peeled—if you're lucky, you might see a 400-year-old shark, a dumbo octopus, or . . . a xenophyophore! Layer by layer, you will get to know all of the mysterious sea life that dwells in the deepest depths while finding out just how interconnected—and crucial—the ocean’s ecosystems really are.