Hikaru, a cheerful librarian, catches the eye of a lesbian gyaru couple, Mito and Monaka, on her train commute. Determined to seduce her, they begin to grope each other's breasts and provoke her with passionate kisses in front of her. Hikaru, unaware that it's a seduction scheme, scolds them: "You shouldn't do that on the train!". Thanks to the gyaru's easygoing nature and Hikaru's own cheerful personality, the three quickly become close friends. However, as their girl talk heats up, Hikaru begins to feel a sense of unease at Mito and Monaka's increasingly frequent physical contact. The two's actions gradually escalate, and they lock Hikaru's thighs in a "double crab-claw hold" from both sides, then extend their fingertips toward her defenseless private parts. Though bewildered, Hikaru is gradually developed into a lesbian by Mito and Monaka's crab-claw technique, and she starts to look forward to her commute home where she can meet the two of them.