Magical Security Organization.There is a lingerie thief in Tenbi Academy and Maken-ki are responsible for catching them. The thief proves to be highly elusive and difficult to track at the very least, with more girls falling victim to their perverted antics. After multiple failed attempts from the girls to do surveillance of the bathrooms, Takeru deduces that the lingerie thief is stealing bras in ascending order of cup size. When the girls use Takeru's theory to devise that the next victim is either Chacha or Haruko, they plant them in a girls' changing room as a trap and assign members to watch the exits. Though Kengo succumbs to the temptation of an adult's magazine as a distraction and the thief impersonates him to get inside, Takeru defeats the perverted thief in order to save the two. The thief is then apprehended after being revealed.