Shirogane Takeru was living a peaceful life as a 3rd year high school student with his childhood friend Kagami Sumika. However, one morning Takeru awakens to see a mysterious girl named Mitsurugi Meiya sleeping in his bed.
Thus begins the start of a high school love comedy where Takeru will have to choose between his childhood friend and the girl insisting they are bonded by fate.
Note: Despite the “Extra” in the title, this is the start of the trilogy. Read it first!