Shishimai Rinka was a high schooler who ran a small café named Lion House in place of her grandmother. She lived her life much like any other person her age, but one day, she was caught up in an explosion while returning home on the train alongside her friend, Hitsuji Naomi. In an attempt to save her friend's life, she shields her on instinct the moment the explosion goes off, losing her life in the process. However, before she knew it, she was back at Lion House, happily chatting with her friends as if nothing had happened in the first place.