The sister becomes heavily drunk, her consciousness blurred as the line between reality and dreams fades away. In this state, her younger brother deliberately subjects her to repeated lewd pranks. These acts gradually escalate, leading to forbidden incest. While the sister tries to maintain a firm attitude as an elder sibling, she ends up becoming an outlet for her brother's sexual desires while nearly unconscious from intoxication. At other times, still half-drunk and overwhelmed by sudden arousal, she gives in to impulse and has sex with her brother under the influence of alcohol. The story captures the shifting emotions and changing attitudes of the sister across these various situations.