His mom designed the first habitats for colonists on Mars and Europa; his dad ended a long war. But Dax Zander’s days are full of surfing, hitching rides with whales and exploring the reefs around the family’s undersea home – pretty carefree. Until the morning three aliens arrive, pleading for humanity’s help, as their distant ocean planet has just been attacked. While Earth’s leaders deliberate on a risky mission of mercy, Dax feels a call to leave childhood thrills behind and embrace a greater destiny: fighting for the survival of an entire civilization.