One day, a mysterious package addressed to his father arrives… ‘Masaru’s’ friend says, “That thing is definitely an erotic video!” Masaru, who doesn’t even know of its existence, sneaks into his father’s room and sees his father masturbating… His surprised father, and his sister ‘Riko,’ who rushes in to see what the commotion is about. Feeling sorry for her sexually ignorant brother, Riko decides to educate him using her own body.
