Gekkou (Light Novel)

Gekkou, or "Moonlight", is about the peculiar relationship between a cynical boy and a perfect girl.

Said cynical boy is Nonomiya who spends day in day out in boredom, taking refuge from his dull life in his imagination. One fateful day, he happens upon the notebook of the much-rumored beauty Youko Tsukimori, neglected on the ground. Poking out from it is a scrap of paper with the unexpected title "Murder Recipe". His interest ignited, he immediately stuffs it into his pocket, only to find out the promising recipe contains nothing but scenarios that may or may not lead to deadly accidents, not even worthy of being called a plan.

When he tentatively asks her about it the next day, she hasn't lost anything. But then her father dies. An accident...

Can be read here

Tropes used in Gekkou (Light Novel) include:

Ambiguously Evil: Youko Tsukimori. The whole plot is trying to find out if she's a killer or an innocent victim.
Anguished Declaration of Love: From Chizuru to Nonomiya
Bi the Way: Konan
Bunny Ears Lawyer: Konan claims to be one, saying the only reason he can act the way he does is beacuse he gets results.
The Casanova: Konan
The Chessmaster
Chick Magnet / Kavorka Man: Nonomiya, who despite his morbid personality, has both Youko and Chizuru after him, maybe even Mirai.
Cool Big Sister: Mirai
Expy: The begginning and the main character is somewhat similar to Death Note. A bored and cynical high school student (implied smart) finds a notebook and the notebook causes the plot to begin. The rest of the story is nothing like Death Note however.
Jerkass: Konan. Seriously, what kind of detective flirts with a teenager whos mother has gone missing.
Karma Houdini: Youko if she really did kill her parents.
Nerves of Steel: Youko never freaks out. The times she does freak out is when she is acting.
Ojou: Youko
Self-Made Orphan: If Youko is really a murderer, she has become one in the end.
Smoking Is Cool
Sociopathic Hero: Applies to both Nonomiya and Konan. Both of them don't care much about bringing a criminal to justice and are doing it purely out of self-interest and excitment. In fact at one point Nonomiya actually destroys evidence,namely the murder recipe,because he lost interest in it.
Tsundere: Nonomiya is a male one and consistantly denials his obvious attraction to Youko.
Xanatos Speed Chess: Between Kanon and Nonomiya at a critical point in the story.