is a light novel

Light novel

A is a style of Japanese novel primarily targeting junior high and high school students . The term "light novel" is a wasei-eigo, or a Japanese term formed from words in the English language. Light novels are often called or for short...

 series with homoerotic

Yaoi

In careful Japanese enunciation, all three vowels are pronounced separately, for a three-mora word, . The English equivalent is . also known as Boys' Love, is a Japanese popular term for female-oriented fictional media that focus on homoerotic or homoromantic male relationships, usually created by...

 themes written by Saki Aida with art by Chiharu Nara. It's about a detective who goes undercover and who begins a relationship with his "S" - his spy. It was published in English by Digital Manga Publishing

Digital Manga Publishing

Digital Manga is a company that licenses and releases, in English, Japanese anime, manga, and related merchandise. The company has several subdivisions: Digital Manga Publishing, which publishes Japanese manga, novels and instructional and illustration books in North America with multiple imprints,...

 between May 2008 and February 2009.

Reception

Holly Ellingwood, writing for Active Anime, praised the "gripping" writing of the second novel and enjoyed the suspense of the third novel, recommending it to fans of Yellow

Yellow (manga)

Yellow is a four-volume yaoi manga by Makoto Tateno, published in English by Digital Manga Publishing. It tells the story of two elite drug "snatchers" , Taki and Goh, mainly about the love and adventures they share together....

. Michelle Smith, writing for PopCultureShock, said that she found the fourth volume to be "better than most" other yaoi novels, appreciating that the story was "trying to be about something more than sex".