Mabel lives somewhere curious. It’s called The Mermaid Hotel. One day a mysterious guest checks in. She’s old, old, old, with red lips and twenty-three bags. Mabel decides this gruff-voiced woman is definitely a SUPERVILLIAN. She will have to keep a very close eye on Madame Badobedah (which rhymes with ooooh la la)…and her beady-eyed tortoise. But even supervillains have a soft side, and as an unlikely friendship grows between the pair, their fantastical exploits take them well beyond the corridors of their seaside home.