"Ichika" is my childhood friend who lives in the same apartment building with me since I was little. As I grew up, Ichika became estranged, but suddenly Ichika suggested that we have a drink together on my 20th birthday. When we drink alcohol for the first time, we don't know how much to drink, and before we know it, we're both drunk. I can't help but reveal my true feelings and confess my feelings. "Ichika" also accepts that she is drunk... Having grown up and having sex just once is not enough for us, so we go straight into the morning...