Marino Ōkura begins as an ordinary young woman with no prior sexual experience. Her background establishes her virginity before human traffickers target her during her daily routine. Her capture involves being chased and forcibly taken by two men operating in human trafficking.

Following her abduction, traffickers transport Marino to a secluded estate controlled by a dominatrix named Saki and Saki's unnamed master. This estate becomes the primary setting for Marino's subsequent experiences. During captivity, she undergoes systematic training designed to transform her into a submissive sex slave. This process includes coercive exposure to various sexual acts and mandatory compliance with captors' demands.

The training employs psychological and physical conditioning techniques to break her resistance. Sessions feature explicit acts of humiliation, bondage, and sexual servitude, all orchestrated to enforce submission. Marino initially reacts with visible fear, nervousness, and attempted escape, but these efforts fail against her captors.

Her narrative continues in a subsequent chapter where she is presented alongside two other enslaved women, Momomi and Haruka, as party entertainment. At this event, Marino remains under Saki's direct control and suffers further public degradation and torture. Her role shifts from trainee to an object used for others' gratification within the estate's exploitative hierarchy.

The conclusion of her depicted storyline finds her confined in a cell, chained and awaiting further scheduled sessions. This imprisonment signifies an unresolved status within the narrative.