Author Takeda Super regretted not having drawn the threesome so much that he decided to redraw and make it happen, thereby retconning the original Chapters 31–35.
Equivalent to the main story's Volume 4, this is a collection of said chapters, from the original, pure love timeline, that were published in Young Magazine but didn't make it into the main volumes because they were retconned.
It also includes a newly drawn Chapter 36 that shows how things would have continued had they not been redrawn, contributed illustrations, a letter further explaining the rationale behind the redraw decision, and Takeda Super's debut work, Way Of Life.