Kanojo ni Uwaki Sareteita Ore ga, Koakuma na Kouhai ni Natsukareteimasu

Christmas season.
Hasegawa Yūta found himself single after breaking up last month when his girlfriend had cheated on him. And it was only a few days until Christmas!
After an everyday conversation with his female friend, Mino Ayaka, Yūta met a beautiful girl clad in a Santa suit—In a lane full of couples no less!
Her name was Shinohara Mayu.
Will this encounter with Shinohara turn out to be the Christmas present for Yūta ?