Hensuki: Are you willing to fall in love with a pervert, as long as she’s a cutie? ending explained

Hensuki: Are you willing to fall in love with a pervert, as long as she’s a cutie? plot recap, spoiler-light

After finishing his chores by cleaning the Calligraphy Club room one afternoon, Kiryuu Keiki discovers an unexpected love letter waiting for him on the club desk. Eager at the exciting possibility of finally securing a girlfriend, he opens the envelope with great anticipation. Inside, he finds a direct declaration stating I like you, accompanied unusually by a pair of the sender's own panties.

Armed only with this bizarre piece of evidence, Keiki sets out to deduce who among the helpers could be the culprit. He narrows down the potential suspects to four distinct individuals who were present and helped him clean the room that day. These include Tokihara Sayuki, the lazy third-year president of the Calligraphy Club; Koga Yuika, a library committee member of foreign descent; Nanjou Mao, his slightly tsundere fellow classmate; and most awkwardly of all, Kiryuu Mizuha, who happens to be Keiki's own clean freak of a younger sister. Believing that at least three of these girls harbor these unorthodox traits, Keiki determines to uncover which of them will ultimately become his girlfriend through this peculiar romantic mystery.

What happens at the end of Hensuki: Are you willing to fall in love with a pervert, as long as she’s a cutie??