Waka Onoe, a married woman, remains haunted by the traumatic memory of a past penis bandage assault. Aoi Shino, a pharmaceutical sales representative, discovers a clue about the culprit—described in a report as "a woman with a tattoo on her chest"—through her conversation with Waka. Saryu Usui, who works at an insurance company, suddenly forces herself on Aoi during a visit to her workplace, aggressively kissing her before fleeing. At that moment, Aoi spots a tattoo on Saryu's chest. Convinced she has found the perpetrator, Aoi joins forces with Waka to seek revenge. However, they fall victim to Saryu's cunning scheme, and soon Aoi becomes the next target of the penis bandage assault.