The boys are stranded in a small rural town, they hear about a "monster killer" roaming the countryside. At night, they sneak out. Peewee is shot by a grave-digger, and they are forced to seek aid at an old mansion.
The boys are sent to a mountain camp. Stranded en route in a small rural town, they hear about a "monster killer" roaming the countryside. At night, they sneak out. Peewee is shot by a grave-digger, forcing them to seek aid at an old mansion. The owner of the mansion (Lugosi) insists that the boys spend the night. After seeing Peewee walk around the house in a trance, the boys decide that the man turned him into a zombie. They gang up on him and tie him up. The nurse at the boys camp (Dorothy Short) sets out to find the missing boys, taking up with Von Grosch (Dennis Moore) who has come to rid the town of the killer - or has he?—Anonymous
The East Side Kids have been picked up by the cops and are being sent to a camp for underprivileged youths. When the camp bus makes a stop in the town of Hillside, Muggs [Leo Gorcey], Glimpy [Huntz Hall], and Danny [Bobby Jordan] stop at the Village Sweet Shop for root beers and to ogle Margie, the pretty waitress. While in the shop, they hear a radio bulletin about "The Monster," a crazed murderer who kills inhumanely. Word has it that he may be in the Hillside/Colton area.
Also on his way to Hillside is the black-caped Nardo [Bela Lugosi], his mute dwarf servant Luigi [Angelo Rossitto], and three large boxes marked "casket." Not far behind them is Doctor von Grosch [Dennis Moore], the writer of a book about vampires. It's pretty obvious to Lem Harvey [P.J. Kelley], the gas station attendant where both Nardo and Grosch stop for directions, that Nardo is The Monster with Grosch hot on his tail.
After everyone at the camp has fallen asleep, Muggs tries to sneak out for a date with the pretty waitress from the Sweet Shop (Margie), but Glimpy and Danny catch him and demand to come along. As soon as they leave their cabin, Skinny [Donald Haines], Scruno [Ernest "Sunshine Sammy" Morrison], and Peewee [David Gorcey] wake up, put on their pants, and follow.
Meanwhile, Nardo has made it to his destination, the abandoned Billings Estate, after first making a stop at the local cemetery and scaring the caretaker into firing a shot at him. Thinking they are lost, the kids later take a short-cut through the same cemetery. When the caretaker sees them, he fires off another shot, this time hitting Peewee. In their attempt to find help for Peewee, they sop at the first house they see - the Billings Estate. The Estate has no phones or lights, but Nardo has some knowledge of medicine, so he offers to help and also has Luigi prepare rooms for the kids so that they can stay with their sleeping friend Peewee during the night.
Back at the camp, the kids' absence has finally been noticed and are presumed lost in the woods. The self-centered camp director, Jeff Dixon [David O'Brien], decides to leave them wandering in the woods in order to teach them a lesson, but the camp nurse, Linda Mason [Dorothy Short] (who is also Jeff's girlfriend), decides to go look for them on her own. When Linda doesn't return, Jeff heads into town to get Constable Jim [Guy Wilkerson] to round up a search party. Meanwhile, Linda has met up with Dr. Grosch and is on her way with him to the Billings Estate to rescue the kids from The Monster.
Unable to sleep out of worry for Peewee and scared that Nardo may be The Monster, the kids decide to take Peewee and get away from the house, but Peewee sleepwalks and disappears. Scruno thinks Nardo may have turned Peewee into a zombie. When the kids tell Nardo of their plan to find Peewee and return to camp, Nardo warns them that Peewee should not be moved, so they knock Nardo over and lock him and Luigi in the bedroom. They then split up and search for Peewee, getting locked in boxes, disappearing and reappearing in a cabinet, and encountering spiders and skeletons along the way until they finally all meet up again.
The Kids decide that they have to get tough. They cover themselves in a black cape with a skull on top and confront Nardo, telling him that this is the ghost of Mr. Billings and that it is going to kill Nardo. Nardo runs, but the skull falls off the cape and knocks Nardo out, giving the kids a chance to tie him up.
With Nardo securely bound, the kids go back to Peewee's room and surprisingly find him sitting up in bed, totally conscious and totally well. His only memory is of Nardo tending his wound and giving him a sleeping pill. Suddenly, Nardo enters the room, just as the search team arrives at the estate. By the time the search team finds the kids, they have already learned the truth about Nardo and Luigi. Nardo is a magician, Luigi is his assistant, and they have come to the Billings estate to practice some new tricks.
Suddenly a scream is heard. Grosch has cornered Linda in an upstairs room and is about to kill her. Because the door is locked, no one can get in, so the kids lift Muggs through the skylight. He crawls out on the roof and makes his way to the window. Muggs kicks his way in, jumps on Grosch's back, and starts pounding. Linda breaks free, unlocks the door, and lets in the kids, who rush to assist Muggs. Right behind is the search team. Jeff runs to Linda, but she's all right.
Epilogue: Nardo puts on a magic show. For his final act, he makes Margie disappear in his magic cabinet. Muggs thinks he has it figured out and says that he'll go into the cabinet and bring her out. When Nardo opens the curtain, Muggs walks out carrying... Scruno. [Original synopsis by bj_kuehl.]
