On a warm summer afternoon, a group of teenage friends still in high school accidentally cross paths at a mysterious institution: the Museum of Mysteries. Scooby-Doo, a always-hungry Great Dane, and his best friend Shaggy are the epicenters of the chaos, while Fred, Daphne, and Velma join the adventure. Together, they decide to investigate a series of strange phenomena that have begun to occur at their school, including the mysterious disappearance of several valuable belongings.
As they dive into clues and evidence, the quintet finds themselves caught up in a tale of ghosts and urban legends that seem to come to life. The infamous "Ghost Knight," a specter threatening to ruin the school event, becomes the main villain, and the group must work together to uncover the truth behind his appearance and stop his evil plan. With moments of laughter and a couple of scares, this youthful dynamic learns to trust in their abilities and the power of friendship.
As new challenges test their courage and wit, the friends discover their true calling as amateur detectives, laying the groundwork for their future adventures. Declarations of friendship and loyalty are put to the test, all while Scooby and Shaggy, of course, manage to grab a bunch of snacks. The quest not only reveals external mysteries but also the importance of finding their place in the world.