Shiro is a college student who just moved into the apartment next to Tsumugi's. The two of them used to play together, but it's been years since they've even seen each other. They must have both been so surprised!

But Shiro's not very good at housework. His place is a mess. Tsumugi can't let him go on like that, so she sometimes comes over to help out. And it's during those visits that Shiro starts to notice just how grown up his childhood friend has become.

This is the story of how their relationship progresses to the next level...