Part of a series of games focusing on protagonist Youhei Nase and his relationship with different heroines in each volume.

The story shifts to Youhei’s relationship with his younger sister, Yukana. When they were younger, he often traveled to Akihabara with Yukana for her sake, but pretty soon he found himself hooked on Akihabara’s game centers. A certain someone gifts Youhei and Yukana a Christmas trip with each other, and it’s during this time that he gets to know Yukana better.