by Liz Kessler
First published 2025
Emily Windsnap discovers a crystal bangle beneath Rainbow Rocks. The strange jewel pulls her and her mer-friends into a new mystery when they learn it came from Halflight Castle. Emily and Shona swim back to the familiar fortress, where they meet Aaron and Neptune himself, ruler of all oceans. The bangle guides them to caves filled with glowing crystals. With Mandy's assistance, they uncover the jewel's true origins and realize something terrible will happen if they don't act fast. The only way to prevent disaster requires convincing two of the most powerful and selfish beings in existence to work together. Emily and her friends must find a way to make Neptune and the Viking god Thor put aside their own desires to save everyone else.
Genres: adventure, mystery, fantasy, young-adult
Vibes: emotional, suspenseful, whimsical
Tropes: found-family, unlikely-allies
Setting: Halflight Castle, Rainbow Rocks
240 pages · Hardcover · Candlewick