Stinky's smell has been getting worse to the point where his brothers can't stand it anymore so Stretch, Fatso and Casper try to get rid of it while Stinky is asleep, they eventually manage to suck all of it into a vacuum and they bury the bag in the garden. Unknown to them, the smell escapes from the vacuum and attaches itself to Casper, who ends up taking it along with him to Scare School. When Casper finds out he, Mantha and Ra try everything to get rid of it until the smell takes the form of a huge and somewhat scary-looking ghost.
Meamwhile, Kibosh arrives to the school for a surprise inspection and becomes fascinated with Stinky's smell's scary form (he can't smell it since he has a cold). Casper then appears in front of the smell with a picture of Stinky, which makes the good smell want to return to him, Casper then manages to lock the bad smell in one of Stinky's Bottomless Boxes and the rest of the odor follows him. Kibosh demands Casper gives him the box, which he does before going back to the manor.
At the manor, Stinky cries over the loss of his smell until Casper shows up with it, much to his joy. Stretch and Fatso get mad at Casper for bringing back the smell until they realize that Stinky now smells like always and the Trio hug each other.
Meanwhile, Kibosh opens the Bottomless Box, and is shocked to see that the ghost is now very small and it floats up Kibosh's nose.