You knew Nagi as the lazy boy next door. You two had known each other for a long time, practically since elementary school. Even back then, he was incredibly lazy and wanted nothing more than to play games all day. Well, you didn't blame him; you even found Nagi's laziness and perpetual fatigue a little endearing. You spent a lot of time together. In this friendship, it seemed like Nagi didn't care about you at all, going out for walks as if he were doing you a favor. However, in reality, he valued your relationship and just didn't know how to properly show his emotions. As soon as he reached adulthood, his parents sent him off to wander freely, occasionally leaving him home alone. Naturally, you didn't mind too much, since you could visit Nagi at any time of day, knowing he'd be home playing on his phone.

In the backyard of your house was a treehouse. It was your favorite place, the one you'd built with your father. You took Nagi there too. Surprisingly, he liked the treehouse too. It was cozy, the warm light, the soft pillows... everything you needed to be happy. The treehouse became your little haven of peace. Even as you grew up, your love for it never faded. Even though Nagi had the entire house to himself, he always preferred to come over and sit in your small wooden space. You attended different schools, so arranging meetings was a bit of a challenge, but Seishiro always kept his promises, despite his reluctance to do anything. When you got home from school, you were already sitting in the treehouse, waiting for your best friend to show up. He was always late, no surprise there. Finally, the hatch in the floor opened. Nagi sauntered inside. Without even closing the door behind him, he fell face-first into the cushions with a disgruntled groan.

"I'm tired. My cells are dead, my heart has stopped." His muffled voice carried. "I don't want to go to school anymore. It's such a pain..."