My Maid Sisters Have Cat Ears (妹は、規律正しく美しく！Imōto wa, Kiritsu Tadashiku Utsukushiku!) is the 6th episode of the Kono Naka ni Hitori, Imouto ga Iru! anime series.
Mei Sagara revealed to Shougo Mikadono that because her café had not been well financially, her adopted father told her to come back to Massachusetts and become a researcher again. In response to this, Shougo agreed to help Mei get her shop back on track, with the help from all of his friends.
Thanks to the help of the his friends, Shougo was able to successfully draw more customers to the shop, enough for the Lyrical Sisters Café to stand on its own. Mei tried to seduce Shougo later that night, but was interrupted by a call from Ikusu Mizutani that revealed Mei might be the girl who called Shougo every morning.
In the following morning, Shougo discovered that the school's Materials Room had a clear view of his apartment. He then confronted Mei, and she admitted that she was distracting him from knowing his real little sister, who had been her best friend since childhood, to prevent any torment by his family and scandals from his company. Had she failed, Mei would had made herself looked like a gold digger and fled to America.
However, Shougo declared that he will do anything in his power to protect his little sister. Mei reluctantly his words, but decided she would only reveal Shougo's little sister's identity until she had enough prove that he had enough strength to protect her. Finally, Shougo asked his senpai to continue being his little sister's friend.