Em, a 20-year-old virgin, struggles with her newfound desires. One evening, she sees her younger sister's innocent play and feels a surge of lust. She retreats to her room, her body aching with need. She tentatively touches herself, her fingers exploring her untouched folds. She gasps at the pleasure, her mind filling with images of her sister. She knows it's wrong, but she can't stop. She falls asleep, her hand still between her legs, dreaming of her sister's naked body.