From the back of the box : In “Mermaid Rain”, you explore the ocean and gather as many treasures as possible in order to win the heart of your Prince.
But you can’t win the heart of the Prince while stuck in the ocean - you will need to spend some of your treasure to appease the witch, who will transform your glorious fish tail into functional legs. Then, hopefully, you will have enough treasure left to dazzle the Prince.
The main action of “Mermaid Rain” is divided into two phases: the “Surf-predicting” phase and the “Surf-riding” phase. In the “Surf-predicting” phase, you make melds by using the cards in your hand and gain a Surf tile.
In the “Surf-riding” phase of each round, you place the Surf tile on the board, move your Mermaid by using cards from your hand, and gather treasures.
Gain enough treasure and win your Prince!