The story of how I changed and how I changed him ―――Synopsis―――― Yotsuba and Chigusa became step-siblings after their parents remarried. They were close when they were young, but now Yotsuba unilaterally rejects Chigusa, and they barely speak to each other. Yotsuba feels guilty that Chigusa still adores her like she did back then, so she decides to distance herself from her by moving out of the house when she goes to college. However, when she tells Chigusa about it, things get strange and they end up arguing. It was meant to be a case of verbal abuse. But those are words that should never be said to Chigusa... and their relationship changes in an irreparable way. The story is centered around a girl who is overwhelmed with her own concerns and a boy who is desperately trying to keep things together.