"Ichika" is a childhood friend who lives in the same apartment building as me. We've grown apart as we've grown up, but on my 20th birthday, "Ichika" suddenly suggests we go drinking together. It's my first time drinking, and I don't know how to handle it, so before we know it, we're both drunk... I can't help but confess Kokoro. "Ichika" is also drunk, so I accept it... For us adults, having sex just once isn't enough, so we continue until the morning comes...