Mara is a plus-size mermaid, mocked and rejected her entire life by her own family and an entire kingdom of the thin. When her envious sister offers her up as a sacrifice to the forbidden Abyss, Mara finds herself not among monsters, but in a world where fullness is true magical power — and falls in love with its beautiful queen. But the moment the legendary Heart of the Ocean awakens, capable of uniting two warring worlds, Mara has no choice left — she must protect her new love, her people, and herself from her sister's schemes and the cruel King of the Upper Sea, both willing to do anything to preserve an age-old lie.
