The Young Mistress Plays Detective in the Spa Murder 1998 one on netflix

Akane is the young mistress of Notoraku Inn in Ishikawa Prefecture. She is trained by her mother-in-law, Takako, daily. One day, as Yohei, Akane’s husband, and Takako are on their way to a friend’s wedding, Rekiko, Yohei’s childhood friend, confesses her feelings for Yohei in front of everyone at the hotel. The next day, Reiko’s body is found and Akane and Yohei become murder suspects.