義兄が銭湯でお風呂に入っていると、義姉が来ました

There was no water in the sister-in-law's bath house, so she thought of going to the brother-in-law's bath house and taking a bath, but the sister-in-law did not know that the brother-in-law was already taking a bath and as soon as the sister-in-law opened the door of the bath house, her brother-in-law was seen bathing her, then after that a lot happens between the two.