Ruby Gillman, a sweet and awkward high school student, discovers she's a direct descendant of the warrior kraken queens. The kraken are sworn to protect the oceans of the world against the vain, power-hungry mermaids. Destined to inherit the throne from her commanding grandmother, Ruby must use her newfound powers to protect those she loves most. A shy adolescent learns that she comes from a fabled royal family of legendary sea krakens and that her destiny lies in the depths of the waters, which is bigger than she could have ever imagined.