The renowned creators of One World: 24 Hours on Planet Earth follow up with a lyrical book exploring the wild wonders of the sea--and how the oceans of our big blue planet converge as one, teeming with life. Two children and their grandmother discover a "sea heart" on the beach: a smooth, round bean the size of one child's palm, which has traveled the world on the Gulf Stream's current. The trio traces the bean's wondrous journey on a map--through seagrass meadows brimming with turtles and tiger sharks, coral reefs, underwater mountains traversed by whales, and kelp forests bobbing with seals--until it washes up, a full year later, on their rainy beach in Scotland. Narrative nonfiction at its best and most beautiful, this companion to One World from zoologist Nicola Davies and award-winning artist Jenni Desmond is a fluid, well-researched story about the way currents connect us all to the vast ocean that colors our planet blue. Tackling, too, the global impact of humans on the ocean--especially the perils of plastic--the book employs fascinating facts, gentle urgency, and specific conservation success stories to point a wise and hopeful path forward.