Higa Shimai Series

Hideki Tahara and Kana Tahara are newlyweds. Hideki is excited about his future with Kana. One day, a mysterious person visits the company where Hideki works. Hideki's colleague conveys the visitor's message to Hideki "about Chisa-san case.” As soon as Hideki hears the name Chisa, he becomes stunned. His wife is pregnant and they have picked the name Chisa for their baby. Only Hideki and Kana know the name. Soon the colleague that talked to the visitor has a mysterious death.

2 years later, more mysterious cases take place around Hideki. He is then introduced to freelance writer Nozaki and his girlfriend Makoto Higa.

(Source: AsianWiki)