Kate is a mermaid and is the last. She buried her (mermaid) family decades ago. She lives as a human, collecting beach glass to sell, and hasn't been in the water for a 100 years. Cooper was diagnosed with terminal cancer. He opted to move back to his childhood home. He notices Kate on the beach. This was nice, short and sweet. The epilogue was important, otherwise I would have thought this had a completely different ending. A little more explanation would have been nice, but considering the length, didn't happen.