Heaven's Memo Pad(2011)

Narumi Fujishima is an ordinary high school boy who remains isolated from his fellow classmates. One afternoon fellow classmate Ayaka Shinozaki invites Narumi to join the gardening club and introduces him to a reclusive detective named Alice. Alice hires Narumi as an assistant and puts him to work solving the strange mysteries of Angel fix, an illegal drug. Little does he know it could put him and Ayaka in serious trouble.