Shaggy Rogers, Matthew Lillard, and the rest of Mystery Inc.—including Fred Jones, Frank Welker, and Scooby-Doo—head to sunny Florida for a break that’s meant to ease Fred’s well-known nets obsession. They arrive at Daphne Blake’s uncle Sandy Blake’s hotel, where Daphne Blake, Grey DeLisle, and Velma Dinkley, Mindy Cohn, hope the change of scenery will offer a calmer pace for the group. The hotel is a focal point of the local scene, and the visit comes with the family connection of Sandy Blake, portrayed by the film’s cast, stirring both welcome and tension as old mysteries seem to lurk beneath the surface of a seaside retreat.
From the moment they settle in, trouble follows in the form of a shape-shifting sea monster that keeps raiding the property for jewelry. Fred’s net-centric methods fail to capture the culprit in their first encounter, which only hardens his fixation and adds a comical strain to the vacation mood. In parallel, Daphne tries to help him unwind by steering him toward nets-free zones, but the lobby and the beach are saturated with nets everywhere, underscoring the madness of Fred’s crusade. The gang remains focused on protecting the guests, while the locals whisper about the strange attacks that have the hotel on edge.
Velma heads over to Kurt’s hotel, the rival next door, where the atmosphere of competition between the two properties is growing. Kurt, Daran Norris, seems almost amused by the mayhem, as the repair delays to a holographic water show—meant to be the marquee attraction at Kurt’s place—linger and point toward a larger problem: Brownstone Industries is dragging its wheels on the fix, leaving the whole seaside town in suspense. Meanwhile, Shaggy starts to feel neglected when Scooby spends more time with Shana, a guest’s dog, and he opens up to Kiki Brownstone, Melissa Rauch, the owner of the dog and the wife of Grafton Brownstone. Like Shaggy, Kiki finds herself lonely as her canine companion remains with Scooby, deepening the emotional currents that will soon intertwine with the mystery at hand.
That night, during a lively hotel party, the monster returns, once again drawn to Kiki’s necklace. The gang uses a clever trap—built by Fred from video cassettes—as the monster is lured into sight. The creature’s tentacle reaches for Velma Dinkley, Mindy Cohn—a moment that heightens the tension and tightens the crew’s resolve to solve the riddle behind the perils. As the trap tightens, Fred captures the person behind the monster: Grafton Brownstone, Kiki’s husband and the head of Brownstone Industries. It becomes clear that Grafton had sold Kiki’s necklace for money, and the necklace she wore was fake. His plan was to keep the deception hidden and steal the real jewelry while Kiki remained unsuspecting.
With Grafton’s arrest and the revelation about the necklace, Kiki and Shana—who is the dog tied to the case—seek bail for Grafton, while Scooby and Shaggy find common ground once more. The investigation closes with a return to friendship and partnership among the Mystery Inc. team, whose vacation derailed into a case that tested trust, loyalty, and the group’s ability to read beyond flashy distractions. The Florida getaway ends on a note of quiet reconciliation, and the gang steps back into the night with a clearer sense of how their nets, both literal and metaphorical, can be used to catch not just monsters, but the truth behind each mystery.
