The Professional Tarpon Rodeo is back on Sanibel Island, offering any celebrity contestant who lands a rare piebald tarpon a one-million-dollar prize. But marine biologist Doc Ford is certain that people are cheating to win. When an angler team illegally catches a tarpon to feed it to sharks for attention, Doc enlists the kids of Sharks Inc.—Luke, Maribel, and Sabina—to uncover their scheme. Would introverted Luke rather be trapped between a hammerhead shark and an injured tarpon—or trapped in the spotlight of internet adoration? With the help of an unlikely new friend, the intrepid Sharks Inc. trio will unmask a band of zombies, outwit a devious celebrity manager, and rescue one elusive tarpon.