Scooby-Doo! Meets the Boo Brothers

Shaggy learns that his uncle, Colonel Beauregard, has died and left him Beauregard Manor. He travels with Scooby and Scrappy to claim the inheritance, despite warnings that the estate is haunted. The plan to claim the fortune sets the stage for a string of eerie discoveries.

Sheriff Rufus Buzby warns them that Beauregard Manor is haunted and urges them to turn back. He mentions a circus train derailment that has freed a dangerous ape nearby. The warning does little to deter the trio from continuing toward the estate.

As they drive, the road passes through the family cemetery where eerie phenomena begin to occur. They encounter the Headless Horseman and a ghostly wolf watching from the trees. These spectral appearances heighten the sense that the estate is truly cursed.

They finally reach Beauregard Manor and meet Farquard, the late Colonel's creepy manservant, who claims a vast jewel fortune is hidden on the property and that Shaggy has no rightful claim. His warnings clash with Shaggy's curiosity and the lure of treasure. The mansion's atmosphere grows heavier with each step.

Before they can decide what to do, their truck sinks into quicksand on the grounds, trapping them inside the estate. The trio must spend the night surrounded by strange noises and a growing sense of danger. Ghostly activity intensifies as Farquard's warnings echo in their minds.

Shaggy suggests calling in a ghost-exterminating team, and The Boo Brothers arrive—three ghostly versions of The Three Stooges. They set out to drive away the hauntings, though their efforts mostly cause more chaos than clearance. The siege of specters continues with little relief for the trio.

Shaggy meets Sadie Mae Scroggins and her gun-toting brother Billy Bob, who share a feud with the Beauregards. Sadie quickly falls for Shaggy, while Billy Bob threatens him, complicating the trio's investigation. The family feud adds tension to the treasure hunt.

In the kitchen they discover proof that the jewel treasure is real—a diamond ring and a letter from the late Colonel with a treasure clue. The discovery motivates the gang to start a treasure hunt, despite Farquard's protests and Sheriff Buzby's warning about the ape on the loose. The hunt expands to the mansion and plantation.

As they chase clues, ghosts—Colonel Beauregard, the Headless Horseman, and a skeletal Skull Ghost—haunt their progress. They push through eerie passages and traps, even contending with a bear and the escaped circus gorilla. The mystery deepens as the hunt tests their courage and teamwork.

The lost truck is found again, sunk in a secret underground tunnel beneath the estate. It reveals that the treasure hunt is more than a simple treasure map and connects to hidden passages on the property. The underground route adds physical peril to the supernatural obstacles.

The final clue leads them to the mansion's fireplace, where the treasure is hidden. The Skull Ghost holds the trio at gunpoint, attempting to claim the jewels for himself. The treasure pours out of the fireplace, trapping the Skull Ghost beneath a heap of gold and jewels.

Sheriff Buzby arrives and unmasks the Skull Ghost as his greedy brother, T.J., exposing a larger impersonation plot alongside the remaining ghosts. The real Sheriff explains the ruse and ties up the mystery of who was haunting the manor. The truth restores order and clears the ghosts' reputations.

With the treasure found, Shaggy agrees to let the Boo Brothers have a home to haunt, and the jewels are placed into the Beauregard Trust Fund for Orphans. He and the dogs drive home, their adventure ending with the Colonel Beauregard’s ghost appearing one last time as they speed away. The case closes with a mix of humor and heart.