Before Tater Tagger is taken to prison for robbing a coin shop, he has a secret task to complete. After stuffing a piece of paper and the stolen coins into an old rum bottle, he buries the bottle in a bucket of drying cement and takes it out into the mangroves to hide it. Then he asks his brother, Tots, to watch his dog while he's in prison.
Five years later, eleven-year-old Ami, a cub reporter for her school's TV newscast, learns of a community-wide mystery: dogs keep disappearing suspiciously. Jumping on the case, she and her friends Rico and Gil investigate the apparent dognappings, starting a livestream Facebook report and entering her Boston Terrier, Lewis, in a contest to raise awareness about the vanishing dogs.
Then she and Rico spot a man kayaking in the mangroves. Soon after, she learns that the dognapped canines are all Boston Terriers. Is Lewis in danger? When Ami starts receiving threatening messages from someone called MadDog, demanding she hand over her dog, she realizes the only way to nab the dognapper is to give him what he wants-Lewis.
Can Ami and her friends solve the mystery and keep Lewis safe?