"Silver on the Tree" is the fifth book in the Dark is Rising series by Susan Cooper. It follows the adventures of a group of children and their allies as they confront the forces of the Dark. The story weaves together elements of Arthurian legend and Celtic mythology, exploring themes of good versus evil. In this installment, the characters embark on a quest to find a magical tree that holds the key to defeating the Dark. They face various challenges and encounter mythical creatures, all while learning about their own strengths and the importance of unity in the fight against darkness.