Having deceived the monks of the Unification League into finally leaving by faking Touhou Gessho's death, Tosan Koko takes the boy in as repayment for his having saved her life. Thus, time passes and Gessho lives his life with the Tosan. However, 10 years later, Gessho suddenly decides to leave Tosan for reasons unknown. Yaya has always been mystified by this but Gessho insists that it is all part of his and Koko's dream.