When the soldiers of Fort Laxdo mysteriously fall ill, Shirayuki is sent for to find out what happened and seek a cure. She discovers that the sickness is caused from burning toxic wood left at the fort by a group of bandits, who took advantage of the soldiers' illness to plunder the armoury. Shirayuki strains herself to the point of exhaustion to prepare medicine and care for the soldiers, who fortunately get better within a few days. At the same time, Obi is sent to find the bandits who are confronted and defeated by Zen and his party. Through this ordeal the relationship with Zen and Shirayuki deepens, and she also earns the respect of others.