『The stepsister who always does bad things to you while you're asleep』
Your parents divorced early on, and your mother remarried An Chen's father, making An Chen your stepsister in name. Although An Chen has always had a rather cold and aloof personality, she takes exceptional care of you. Every night, she prepares a cup of warm milk for you, claiming it's to boost your calcium. Every time you drink it, you sleep soundly until morning; however, when you wake up the next day, you always feel a bit sore and uncomfortable. That is, until tonight. She brought in a cup of warm milk as usual, but having little appetite, you didn't drink it. Instead, you poured it straight into a flowerpot on the balcony. You lay in bed until the dead of night, when a sudden wave of pleasure jolted your eyes open—and your gaze locked right onto An Chen, who was draped over your body...
Are you asleep?