The series Graded Readers for Chinese Language Learners is composed of 50 books, divided into three subseries, namely folktales, literary stories and historical stories, corresponding to Levels 1-3 respectively. 
 
Havoc in Heaven tells the story of the birth of Monkey King and the havoc he made in heaven.
On the Mountain of Flowers and Fruits there was a monkey born from the stone who set out to sea in search of the immortals to learn the way of immortality.
He found an immortal, from whom he learned amazing skills, including going to the heaven and the earth and changing into 72 forms. His master named him Sun Wukong. Sun Wukong caused turbulence in the Dragon Palace of the East Sea and took the golden cudgel away as his own weapon. He also intruded into the Palace of the Underworld and caused trouble there. When the Heavenly Emperor sent troops to fight him, he made havoc in heaven. At last, Buddha from the west subdued him and trapped him under the Wuxing Mountain.