After the final drive with Setsumi,
Himeko has once again returned to the 7th floor.

Himeko has but a single regret. -- Her best friend Yuka.

Only Himeko knew about Yuka's timid and unreliable personality.

There is little time left. Her life will run out in one month.

In that time, there is something Himeko wants to do for her "best friend" ...