Sweet and somewhat awkward 16-year-old Ruby Gillman just wants to fit in with her peers at Oceanside High, but feels she’s invisible. She helps a classmate she has a crush on with math, but he only admires her for her skill with fractals. He can’t hang out with the popular girls and boys at the beach because his overprotective mother strictly forbids him to go in the water. But when she finally breaks her mother’s main prohibition, Ruby discovers that she is descended from the great warrior queens of the Kraken and is destined to inherit the throne of her demanding grandmother, the Warrior Queen of the Seven Seas.