Newly married ninja Ayame is assigned her most dangerous mission yet: To infiltrate Lord Amakusa's castle for an undercover investigation. Acting as a mercenary for hire, it will take all of Ayame's skill and willpower to uncover the truth and return home to her husband.

Ayame is a ninja of the Oboro-style, a clan of deadly assassins trained to move as swift as lightning in their mission to deliver judgment to those who deserve it. Her newest assignment is as dangerous as it is important to the newly married ninja: If she succeeds, she can resign honorably and live together with her husband.

The target for her last mission is Amakusa Castle, home of a powerful general rumored to be involved in slave trade. Tasked to uncover the truth, Ayame acts as a mercenary for hire to gain Lord Amakusa’s trust. Forced to follow his crude orders to remain undercover, her mission quickly turns into a test of willpower. Will Ayame be able to keep her senses and return to her husband after the mission is over, or will she succumb under the general’s advances becoming his next concubine?