On her way home, a little mermaid slipped and fell into a lost ancient city. The city has crumbled, and only its old drainage pipes are still intact. To get her home safely, you need to pull out the pins in the right order.
Each level is a section of pipes blocked by pins. Pulling a pin lets water, treasure or danger flow through. A hungry shark is lurking and wants to eat the mermaid, so make sure the pins holding it back stay in place until it is safe. Work out the right order, guide the mermaid through and keep her out of harm's way.