Mr. Wilson slips on Dennis' skateboard and has to go to the hospital. Once there, Dennis arrives to cheer Wilson up... Wilson is in for the time of his life! The kids discover an abandoned old gothic house that Dennis decides would make a great club-house. The kids begin cleaning the place up until a pair of ghosts appear! The others want to leave the place, but Dennis who never once sees the ghosts chides them for being scaredy cats, and gets them to stay. Finally the "ghosts" are revealed as a couple of crooks who are using the old house to hide their ill-gotten gold, and using "scare tactics" to frighten the kids away. Dennis saves Margaret's life, and she won't let him forget it. Desperate to get Margaret out of his hair, he tries to arrange to have the girl save his life. All his efforts are futile...until an escaped grizzly bear happens on the scene. (thetvdb.com)