While the house is being renovated, a father and son are staying with the father's sister. The father and sister are in the hospital, so the father and son are living together in a six-tatami room with the three daughters. However, the six of them are living in a six-tatami room, and it's so cramped that the three busty sisters' plump breasts and buttocks touch each other, which makes the son excited and aroused. The three naughty sisters start to secretly seduce him...