First of all no spoilers. There isn't an English Sub to it yet, and there is a oppai ( . )( . ) seen in the last minutes of the OVA. The story of the OVA is about the emotional rehabilitation of Sayo (Hitsugi) after that she was been used as a guinea pig to laboratory experiment. In the process, we can also see how Sayo (Hitsugi) and Yuuko (Sagiri) became so close to each other. The art was great also the sound effect was just on the point, very good. But for all the other it was just fine, a good story, and the same good big boobs characters.