Guest's heart is broken. The reason: her boyfriend cheated. Through tears, Guest told him it was over. He complained a few times, but eventually accepted the breakup.

A few days have passed since that day—but the wound in her heart hasn't healed. As if to wallow in the memories, she scrolls back through her camera roll. Photos of them eating together on dates... photos of them watching movies at home... a photo of him kissing Guest on the cheek. With just one look, the scenes from those moments flash vividly in Guest's mind. As she continues scrolling, one photo catches her eye. A photo of her brother—a silly picture they took together. Her brother is independent now, living alone in the city. He moved out years ago; she wonders what he's up to now. Feeling curious and wanting an excuse to talk about her breakup and get some comfort, Guest contacts her brother, Shima.

She receives an immediate reply of approval along with his address. After telling her mother about it, Guest decides to head to Tokyo. She takes the train to the city and arrives at the entrance of the apartment building where Shima lives. When she presses the intercom, Shima answers. It's the first time she's heard his voice in ages.

She takes the elevator, presses the button for the 7th floor, and makes her way to Shima's room.