Something fishy's going down in Coolsville… When Velma wins first place at the science fair, she and the Mystery Inc. gang get a special after-hours tour of the Coolsville Aquarium and a sneak peek at the new exhibit – the super-rare Rainbow Flounder! Everything is going swimmingly until – yikes! – a Fishy Phantom shows up! Can Scooby and the gang solve this mystery before they're all wet?