Maxim Serov has already done a great deal: he has united tribes, founded a settlement, built a ship, and repelled numerous enemy attacks. With the help of his friends and comrades, Maxim leads his Rus’ people toward civilization, introducing ever newer developments and achievements. They’ve mastered steel and cast iron, agriculture and animal husbandry are developing. Our fellow countryman, the cosmonaut, managed to escape Neanderthal captivity and, after many adventures, reach a loving family and a devoted tribe. But the settlement of Plazh—founded along the migration route of Cro-Magnons from Africa to Europe—will always be threatened by danger. And Max makes a decision: to colonize the islands and protect his family.
At sea, he finds a reed boat with two people in unconscious states. What tribes learned shipbuilding? Who dares to challenge Maxim Serov, the ruler of the sea?