The Secret - Season 1

Kanako (Chikako Kaku), who works at a department store, befriends a customer, Mario (Shiro Sano). Mario hints at marriage, but when he learns that Kanako is pregnant, his attitude changes completely.

The sudden reunion with Mario (Shiro Sano) had confused Kanako (Chikako Kaku). One night, at the Kuribayashi family where the couple were invited, Kanako sat with Mr. and Mrs. Yamada.

Mario (Shiro Sano) invited Shingo (Yuichi Haba) to Yamada Shobo as a candidate for executive. Shingo is happy, but Kanako (Chikako Kaku), who does not trust Mario, does not agree.

An incident occurs in Kanako (Chikako Kaku)'s apartment where a fire extinguisher is lost, and it is rumored that the culprit is Shingo (Yuichi Haba). Kanako, who is in distress, is rescued by Mario (Shiro Sano).

A note is found in the apartment that says "Shingo (Yuichi Haba) is a murderer", and Kanako (Chikako Kaku) is harassed again. Shingo tells Kanako, who is angry, about a certain past.

Shingo (Yuichi Haba) discovers a photo of Kanako (Chikako Kaku) wearing sheets. Kanako sees the photo and is convinced that the mysterious incident is the work of Mario (Shiro Sano).

Miyuki (Chisato Yamasaki) is fiercely jealous of Mario (Shiro Sano) and Kanako (Chikako Kaku).

Kanako (Chikako Kaku) has completed fertility treatment, but Shingo (Yuichi Haba) is found to have male infertility. Meanwhile, Aiko (Yoko Nobi), who learns of the relationship between Mario (Shiro Sano) and Kanako.

Mario (Shiro Sano) is appointed president when Miyuki (Chisato Yamazaki) becomes pregnant. Mario, who greeted him at the president's inauguration party, became agitated as soon as he saw Kanako (Chikako Kaku).

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.

Kanako (Chikako Kaku) and Mario (Shiro Sano) learn that Miyuki's (Chisato Yamasaki) pregnancy was a kyogen. That night, Kanako confesses her relationship with Mario to Shingo (Yuichi Haba).

Shingo (Yuichi Haba) decides to start over with Kanako (Chikako Kaku). One night when it was decided to move, Kanako entered the study of Mario (Shiro Sano), which was left burnt out.