El-chan is a spoiled girl who loves her brother. When she and her brother, who is a good friend, touch each other's bodies, she feels something itchy between her legs! When her brother checks her between her legs, she is surprised to find that her panties are soaked! It seems that El-chan was in a horny mood without knowing it! So the perverted brother, who is a loli-boy and a siscon, decides to step in and teach his sister about naughty things!