"Since that day, my love has kept directing to you..." In a certain autumn day, the two was tightly bonded under the sunset... A half of a year passed, Yui and the protagonist are now studying for the university entrance examination. The protagonist once got the lowest grade in the school, but recently he shows the drastic improvement. One day, Yui is challenged by the protagonist to do something. At first she was unwilling but finally she accepts his challenge. The loser must obey to the winner... This battle is about to explode...!!