Orcas are the rulers of the seas. These majestic marine mammals have captured people's hearts through their intelligence and complex family structures. But ever since killer whales started attacking boats off Gibraltar, many people have wondered: Are they threatening us, or are they just trying to play?Singer and orca enthusiast Sarah Connor narrates, giving the orcas' stories special depth. The two-part documentary shows the specialized hunting strategies and highlights the social intelligence and precise cooperation of the animals. Older family members give the offspring "school lessons" in body control. But the emotional side of the whales also comes into play: how they mourn when a family member dies and how they have fun.