missing piece by nakajou hisaya
sawatari ai is a bright and cheerful high school student with many friends. always on the lookout, she's surprised to find a new guy in her class, akizuki tooru... but according to her classmates, he's been in their class forever! why is ai the only one who can't remember him? and yet why does he seem to be familiar around her? to make matters worse, a drug scandal breaks out in school! what's going on?