A sultry summer day … – Rina on her way home from shopping tries to enter her house, but inadvertently slips her hand and throws her luggage away. – Yamada, who lives right next door, is back there. – Yamada picks up her luggage with Rina and notices that the sweat on Rina’s neck flows down into her cleavage. – From the depth of the valley, it’s easy to imagine that Rina’s breasts are tremendously large, and it’s clear that the protrusions that stick out from the fabric of her clothes are Rina’s nipples … – Yamada finds out that Rina is a bra, and her reason is upset.