High Quality Content by WIKIPEDIA articles! To Green Angel Tower is the third and final novel in Tad Williams` Memory, Sorrow, and Thorn trilogy. Due to the length of the novel, the paperback version had to be split into two separate volumes, known as To Green Angel Tower: Part 1 and Part 2. In the United Kingdom, the two paperback volumes were titled To Green Angel Tower: Siege and To Green Angel Tower: Storm. The saga follows a young man named Simon as he is caught up in an epic adventure.