Struggling to make ends meet, Sato, a financially challenged university student, seeks assistance from Kaname and Hata. They present him with a lucrative yet mysterious job opportunity that he accepts without hesitation. Little does he know, this decision leads him into a world of unexpected twists as he unknowingly becomes a test subject for a clandestine yaoi study. As Sato delves deeper into this enigmatic realm, he finds himself embroiled in a series of provocative experiments involving anal expansion, nipple stimulation, and S&M trials. Unaware of his friends' true intentions, Sato gradually descends into the captivating yet perilous BL universe.