Only three stones of power remain, and only the eight descendants of Zubin can wield them. A ruthless and power-hungry man is intent on stealing the stones, murdering the three leaders of the fleet, and torturing the secrets of navigation from their children.
Grand master Astreya gives his daughter Mairi command of a ship with instructions to keep the younger members of his family far from danger. However, safety is elusive.
Mairi must face political turmoil ashore, resolve conflicts with her twin brother Trogen, and lead her young crew through storms, dangerous passages, and battles at sea before she can discover the secret that will lead to the river of stones.