A monster has appeared in House Nuir! Meilia's life is in danger...!!While journeying toward Senri's hometown to retrieve the tools that can repair the palace portal, Yui encounters a sickening miasma billowing through the forest. It turns out the source of the noxious substance is none other than the Nuir estate, where an enraged spider monster is on the loose--with Yui's sister, Meilia, trapped inside! Yui wants nothing more than to rush in and retrieve her little sister, but a crisis like this can't possibly be handled alone. With everyone's forces combined, can Yui and her friends stop the monster from unleashing terror upon the country and save Meilia before it's too late?