Hikaru Minazuki dislikes wearing bras and always goes braless at home. However, her family is aware of her habit, and her father in particular keeps reminding her to wear one. Hikaru is skilled at evading his warnings and always finds ways to avoid complying. Meanwhile, her older brother secretly takes hidden camera photos of her with his smartphone. When she discovers his actions, Hikaru angrily confronts him. Amid these everyday tensions, the story unfolds with delicate psychological depth and intense, heart-pounding developments, exploring how family relationships shift and evolve.