A toy rubber duck is found in Scare School. Thatch begins trying to frame Casper for bringing it in. He even tries sneaking another ducky into Casper's bag during class. Casper, realizing that someone is trying to get him into trouble, decides not to immediately suspect Thatch and investigate. He finds a piece of velvet on one of the duckies. While Mantha and Ra try to find a match for the fabric, Casper searches for a match for a piece of wood he finds. Mantha and Ra don't succeed. Meanwhile, Casper finds Cappy repairing his ship. Cappy complains about how no one makes the same kind of wood anymore and he has to use wood from old vampire coffins. Casper compares the wood Cappy's using with the splinter of wood he found earlier. It's a match! Casper heads back into the school and inspects Thatch's coffin. It's the same wood and is also lined with the same velvet found on the ducky. Casper finds a loose nail in the bottom of the coffin that, when pulled, opens up a secret stash of rubber duckies. When Mantha and Ra return, Casper informs them on Thatch's secret. Even though Thatch tried to get Casper in trouble, he comes up with a plan to keep Thatch from being expelled from Scare School. ... Later, Alder and Dash announce to the whole school that it was only Beaky, Cappy's parrot, putting duckies on Cappy's shoulder while he took breaks. (Cappy has patches over both eyes and would not have noticed this.) The last seen of the episode is Thatch in the back of the group of students secretly taking out a pencil and a rubber ducky and drawing vampire features on the ducky's face.