"Over the Garden Wall - Avventura nella foresta dei misteri" narra la storia di due fratelli, Wirt e Greg, che si ritrovano sperduti alla deriva del tempo in una strana foresta chiamata Ignoto. Sperando di ritrovare la strada di casa, Wirt e Greg sono costretti a vagare in questo strano luogo, aiutati da un vecchio saggio taglialegna e da Beatrice, un uccellino azzurro dal carattere impossibile.

A New York commercial artist and his wife and daughter move to a quiet, rustic New England village they visited during their travels, only to find themselves mixed up in ritualistic lifestyle full of foreboding secrets.

19-year-old Egor Chudinov goes in search of his parents, who disappeared during an ethnographic expedition to the Perm Region. Together with his uncle Nikolai and two random fellow travelers — students of philology Tanya and Nadia - Egor moves deeper into the territory, which lives according to its own laws and traditions. There is a gloomy nature here, hermits live in forest dugouts, diseases are treated by sorcerers, and the cause of troubles is considered to be damage caused by witches, and somewhere among the dense forests a bear shaman wanders. At first, Egor is skeptical about the stories about ancient creatures of Komi-Permian mythology, but gradually realizes that the world is much wider than his ideas.