The surprising similarities humans share with whales; Steve goes on an underwater expedition to learn about singing humpbacks, matriarchal sperm whales and playful dolphins and examines how humans early fear of whales eventually turned to wonder.

Steve encounters the largest and most sophisticated hunters on the planet; he reveals the ingenious strategies used by whales that gets extraordinary predators in trouble.

Travel to places where migratory whales feed, breed and raise their young despite imminent danger; Swim thousands of miles for a once-in-a-lifetime encounter with a southern right whale that's about to give birth, then meet a curious humpback calf.

Steve returns home to the Atlantic waters of the British Isles as he considers the question of what humanity can do to ensure the enduring future of whales.