The witch Goupile and her apprentice Arthur like their tea piping hot, reading by the fire, and above all lending a helping hand to those in need.

Goupile and her apprentice Arthur love their hot tea, reading by the fire, and above all lending a helping hand to those in need, like their neighbor, the Hémissaire goat, who is haunted by a striking spirit at night, preventing him from growing his fine heads of lettuce during the day. While solving this mystery, Goupile and Arthur discover a strange blue rock that grows and seems to have been created by black magic. To find the answers they seek, they head for the great library.