"Sharklock Bones: Mermaid tails" is the fifth book in this series starring our fish detective Sharklock Bones (obviously a shark ) and his trusty sidekick, a clownfish named Dr. Flotsam. "Mermaid Tails" features a killer whale recently released from prison who is returning to Fish Town and had vowed to get even with Bones and Flotsam for sending him to jail years before. The suspense builds as Bones doesn't seem to be getting any support from the Fish Town denizens to help him defeat the feared Orca from Majorca.