A sudden phone call in the middle of the night.
"I missed the last train, can I come over now?"
Although I knew it was a bit strange to accept my girlfriend's younger sister, Miyu's, request,
I reluctantly let her stay.

She came to my house, took a bath, and relaxed on the sofa.
My eyes were drawn to her voluptuous cleavage peeking out from under her loungewear,
"Are you looking at my breasts? Are you... getting turned on?"
What, was she showing them on purpose? She didn't seem to be inviting me,
but it was clear that she was open to having sex.
She then mischievously brought her soft-looking lips closer to me as if inviting me to a kiss, and my reason collapsed!!
"I won't tell your sister?"
Today I'm going to make a mess of my girlfriend's cunning, devilish, and fun-loving sister!!