Plot summary
Without two cents to pay, they have to sneak aboard the ferry. All the other passengers and crew of the ferry are frogs dressed in fine clothing. Greg feels bad because his frog is nude. They disguise themselves as members of the ferry's band. With encouragement from Beatrice, Wirt reluctantly plays the bassoon as Greg's frog unexpectedly starts to sing, and they succeed in maintaining their cover. When they arrive at their destination, Beatrice, who has been acting strangely throughout the ferry ride, tries to convince them to stay in the Unknown and not to visit Adelaide.
That night, Beatrice flies away to Adelaide's house. Wirt and Greg follow her in secret. The brothers learn that Beatrice originally planned to give them both to Adelaide as servants in exchange for a pair of scissors that would lift the curse from herself and her family. Adelaide attempts to capture Wirt and Greg, but is killed by Beatrice. Beatrice tries to explain that she had a change of heart, but Wirt and Greg are already gone.
Credits
Adapted from Wikipedia contributors, Over the Garden Wall. Exact series, overall episode number and English title matched. Reference markers and illustrations removed; paragraph formatting adjusted.