Otoko Girai na Class no Bijo ga, Jitsu wa Brocon Shitte Shimatta Kekka.

High school student Eiji Mizuno is devastated when his beloved sister reveals she has a boyfriend. Desperate to identify the man who has captured her heart, he secretly tails her on a date, only to discover he is not the only one watching. Aoi Hasegawa, a stunning classmate notorious for her intense dislike of men, is also shadowing the couple with equal determination. In a shocking twist, Eiji learns that the boyfriend in question is none other than Aoi’s own brother, revealing that her misandrist reputation masks a deep-seated sibling attachment. United by their shared distress over their siblings' romance, Eiji and Aoi form an unlikely alliance to drive the couple apart. Their strategy involves posing as fake lovers, hoping their manufactured relationship will spark jealousy or doubt in their respective siblings. However, this pact of convenience forces two people with opposing views on love and family into close proximity. As they navigate their charade, the line between performance and genuine emotion begins to blur, complicating their original mission and challenging their preconceived notions about relationships and each other.