The story starts off with a young girl named Mizuki Yamakawa. She has always found herself wondering what her purpose was in life, and if her life will ever feel fulfilled. She has had friends, and boyfriends in the past, but none ever stuck around for long. Her one friend that's never left is Ayumi Shiro, but recently, she's grown distant. One day, she was reading online when she came across a saying, "Momento Mori," which means, "remember that you have to die." Discover her take on the phrase.