The Secret S01 E10 The Serpent Falls into Hell

"A shocking work that depicts the extreme love-hate between a man and a woman with a strong touch of suspense on the theme of marriage."

Mario (Shiro Sano), who became the president, played a blunder thinking only about Kanako (Chikako Kaku). Aiko (Yoko Nobi) even reveals Shingo's (Yuichi Haba) past to Kanako.