The main character, a mermaid named Cora, fails a spelling test and is kicked off the Singing Sirens group. She can return to the group if she passes her next spelling test, otherwise she will lose her spot to one of beautiful Vivian Shimmermore. The book is written from the point of view of Cora writing in her diary. Hilarity ensues like Cora finding a tiny shrimp under a barrel of toxic sludge. Some of the sludge spills as she tries to free him. She finds it odd that the shrimp is glowing, but leaves him to get home. The shrimp grows and follows her home. She tries to get rid of him by throwing a tuna tied to a coral stick for the shrimp to chase. She misses him as soon as he is gone and then finds herself surrounded by a gang of sharks that are bullies. It seems that when Cora solves one problem another one pops up and she is again distracted from studying for her spelling test. Although the illustrations are limited to black, blue and white they add to the story.