Black Widow Business.

In Osaka, Sayoko Takeuchi indulges in her evil ways. She targets old wealthy men and marries them for future inheritances. She works with Toru Kashiwagi who runs a marriage agency. Sayoko Takeuchi is married to a wealthy elderly man. One day, Tomomi Nakase hears her father was taken to the hospital. She rushes to the hospital and learns her father is unconscious. She also hears for the first time that her father is married to Sayoko Takeuchi. Tomomi Nakase takes the first steps in stopping Sayoko Takeuchi from gaining her father's fortune. She hires private detective Yoshinori Honda to investigate Sayoko Takeuchi and Toru Kashiwagi.