Nagisa Shiota's Forgiver and Lover

Five years since class 3-E finished junior high and so far life goes well for former-natural borne-assassin Nagisa Shiota.That is until he met up with Karma Akabane. The ever so mischievous red head gives Nagisa a bottle of ordinary water and a bottle of coke. Accepting these he is unknowingly taking part in an a experiment. His partner in this is a girl he also hasn't seen for two years since college began... none other than Kayano Kaede.
SEMI-SMUT. . . NO LEMON THIS TIME. NAGISA X KAYANO/AKARI.