Mina no Off Kai

Guy is a web artist (pen name Suzaki) and arranges an offline meeting with all of his "bixi" friends. When the times comes for some reason all of the guys cancel except for an specially cute girl named Mina.

Initially the guy thinks that he is in heaven, specially considering Mina's soft manners and well behaved personality. But eventually he comes to realize why did the rest of the group suddenly canceled and just how much Mina wanted to meet him.

Yandere flags, anyone?