"Scoob!" tells the story of Scooby-Doo's first meeting with his lifelong best friend Shaggy, and how they teamed up with the young detectives Fred, Velma, and Daphne to form the world-famous Mystery Inc. Today, Mystery Inc. has solved hundreds of mysteries and embarked on countless adventures, but Scooby and his friends discover they are facing their most thrilling and challenging case yet: a plot to unleash the "ghost dog" Cerberus upon the world. As they race against time to prevent this global catastrophe, they also uncover Scooby's secret origins and his unimaginably mysterious destiny.