(西村 月子 Nishimura Tsukiko) Tsukiko is a supporting character in the seventh mystery. She is presumed dead after her disappearance six months ago, following the death of her soon to be sister in law. Due to a malpractice, her fiance's sister died, and Tsukiko was the blame. However, it was in fact the doctor Kobayashi's fault, for the sisters demise. But in order to keep the scandal quiet, all blame was on Tsukiko. This lead to Kobayashi's attempt in murder, when he pushed Tsukiko off of a bridge. Little did he know, she would survive and live in another town for the last six months. After hearing about a festival, Tsukihiko decided to appear in the area, which is when Sakon and the others found her. The only problem was, she had forgotten her memory and didn't even know who she was.
Tsukiko makes a small appearance in the last episode, she appears in the audience with her sister Hoshie, to watch Sakon's play.
Tsukiko shows little emotion, most likely due to her amnesia.
- During the six months of having amnesia, Tsukiko worked at a supermarket for a while.