A sudden tragedy derails Ai's life! Raised with deep love and care by her parents, she is sold off to pay off debts. Taken to the mansion of her new master, she is captured by an unimaginable box-like restraint device. Trapped and unable to move, her vulnerable lower body is subjected to brutal training. Gradually, she develops an attachment to her master, choosing to offer her body willingly. Throughout this process, fear and pleasure intertwine, deepening her emotional dependence.