Sometimes when you lose something, you don't know where to begin looking for it. People always say, "Where did you see it last?" But Tuesday knows exactly where she lost her mom. She watched her leave, watched her walk out onto the moonlit beach, each step leaving a silver footprint in the sand. When it happened, Tuesday didn't think it was unusual. Most nights the pull of the moon lured her mom into the inky water. What was unusual was the fact that she never returned. It all feels like too much for 12-year-old Tuesday DiMare when her best friends betray her, but sometimes you have to quit feeling sorry for yourself and a whole new world will open up. And the world waiting for Tuesday is magical....it's the secret world of freshwater mermaids.