The story centers on an ordinary otaku high school student Souhei Yano. One day, two female soldiers from Principality of Krakozhia, Lieutenant Rtgalnikov and Second Lieutenant Haruka suddenly appear in their tanks as his guards. Then an assassin girl from the Grania Republic named Shachirofu also arrives the town to kill him. Unfortunately, none of the girls care about using firearms in or around private houses at all....

[Source: Crunchyroll]

Episode 13 included with the Blu-ray/DVD release.