Deep, deep down, at the very bottom of the ocean, lies a secret world. Through lyrical narration, this spare-text STEM picture book takes readers on a journey to a place very few humans have ever been: the Mariana Trench. The imagined voyage debunks scary myths about this mysterious place with surprising and beautiful truths about life at Earth's deepest point. Deep, Deep Down shows a vibrant world far below, and teaches readers how interconnected our lives are to every place on the planet.