Ruby Gillman is a seemingly normal, slightly awkward sixteen-year-old girl living in the coastal town of Oceanside. Desperate to fit in with the land-dwelling human teenagers, Ruby conceals a massive secret: she and her family are actually noble krakens, royal protectors of the deep ocean who fled the surface to live in disguise. Her
overprotective mother, Agatha, strictly forbids Ruby from ever entering the water, fearing the ancient blood feud between their kind and the mermaids. However, Ruby’s deep-seated desire for normalcy overrides her mother’s warnings, especially when she develops a crush on a skater boy named Connor.During a high school dance, disaster strikes when Connor accidentally falls off a pier into the churning ocean below. Driven by panic and a desperate need to save him, Ruby dives in, ignoring all maternal commands. The moment her body is submerged in seawater, a dramatic transformation occurs. Ruby grows into a colossal, glowing blue kraken, inadvertently displaying her true heritage to the entire town. Amidst the chaos, she manages to rescue Connor, but her secret is completely out.Enter Chelsea Van Der Zee, the new girl at school who instantly claims to be a mermaid. Chelsea plays the sympathetic victim, befriending Ruby and exploiting her insecurities. Chelsea convinces a naive Ruby that she needs the Trident of Oceans—a
mythical artifact currently held by the formidable Grandamma Kraken, Ruby’s estranged grandmother—to broker peace between krakens and mermaids and make Ruby universally loved. Eager for validation, Ruby seeks out her grandmother in the abyss, undergoing a rigorous coming-of-age training montage to claim her birthright and inherit the throne of the ocean.However, the heartwarming family reunion and quest for peace are shattered by a devastating betrayal. Chelsea reveals her true identity as Queen Nerissa, the ruthless ruler of the mermaids, who manipulated Ruby all along to steal the Trident for herself and conquer the surface world. Empowered by the artifact, Nerissa grows to monstrous proportions, threatening to obliterate Oceanside and subjugate humanity.Realizing the gravity of her mistake, Ruby embraces her true identity. She unites with her mother, Agatha, and her powerful grandmother, Grandamma, forming an unstoppable matrilineal force of krakens. In a climactic underwater and shoreline battle, Ruby leverages her unique blend of human empathy and kraken strength. She faces off against Nerissa, ultimately destroying the Trident and neutralizing the mermaid threat once and for all. Victorious and reconciled with her family, Ruby returns to Oceanside, no longer hiding her true self, and finally finds the acceptance and love she always craved from both humans and her own royal lineage.