At home, the defenseless little sister notices her brother's cock getting rock hard as he stares at her panties. She purposely shows off her sex with her boyfriend to her brother, and gets jealous when she sees her brother having sex with his girlfriend, but in reality, the little sister and brother want each other's bodies. When the family is away, they can't hold back their sexual desires and end up having incestuous sex. It's naughty, so the two get even more excited.