Invaders of the Rokujouma!? Collector's Edition 4 (Light Novel)

Contains Volumes 9-11!
Valentine’s Day is right around the corner. Amid all the fun, however, Ruth receives a strange message from her parents back home in Forthorthe... and they want her to get married?!
While trying to get home, Koutarou and Clan encounter a young girl named Kii. Worried that she might have seen Clan’s spaceship, they dig a little deeper into her story. What’s a six-year-old kid doing alone in the mountains, anyway?
Now that the invaders have come to an understanding of sorts, things are going more smoothly than ever in room 106. But can these happy days last forever? Will their newfound friendship be enough to save one of their own when fate comes knocking?