Henrietta is convinced to sign a declaration of war against Albion. News of a victorious battle for the Tristain and Germania allied forces reaches a town that Louise and Saito are currently in. Saito discovers a sailor uniform on sale at a clothes merchants shop, and buys it, opting to give it to Siesta rather than to Louise. Upon returning to the academy, the two join Agnes and Julio on exploring a secret archive hidden beneath the school, which Agnes was denied permission. Agnes wishes to obtain the information there regarding her home town of D'Angleterre's burning to help carry out her revenge against those involved. Eleonore is picked to open to lock to the entrance. As the group heads farther down, they are joined by Siesta, who is wearing the sailor uniform Saito gave her earlier. After discovering that Saito gave the sailor uniform to Siesta because Louise lacked the chest size to make it look good, Louise blows a part of the cave in the way they came. With little to do but move further, the group finds the archives and are sent to look for the records regarding the town of D'Angleterre's burning 20 years ago. When Siesta trips and makes a mess of the books, Eléonore returns them to their proper place with magic, which triggers the archives' security system and begins to bring the bookshelves to a close. Agnes finally finds the information regarding D'Angleterre's burning, but a part of the page that lists the person who led the attack is missing. The group narrowly escapes the collapsing of the bridge that led them to the archives. Upon realizing that Louise had blocked their way out from before, Julio grants Saito permission to have intimate moments with Siesta. Siesta is happy to oblige and Saito also thinks it to be a good idea, however, Louise is watching and is preparing to blow something else up. When Saito points out that the cave in she made earlier is in the opposite direction, Louise tells him to shut up and blows them up anyway.