"To Green Angel Tower" is the concluding volume of the fantasy series Memory, Sorrow, and Thorn by author Tad Williams. The story follows the journey of several characters as they confront the dark forces threatening their world, particularly the evil Storm King and his minions. The narrative weaves together themes of friendship, sacrifice, and the struggle between good and evil. As the characters unite to face their challenges, they discover the importance of hope and resilience in the face of overwhelming odds, culminating in a climactic battle at the titular Green Angel Tower.