Invaders of the Rokujouma!? Volume 18

The Satomi band of knights is steadily expanding and all is well in room 106. At least for a little while. Yurika comes to everyone with an unusually serious request—she wants them to help her savior and mentor, the former Rainbow Nana. Children then mysteriously start going missing in Kisshouharukaze City, which can only mean one thing. The evil magical girls of Darkness Rainbow are back in town and they mean serious business this time. Deadly serious business.