Futaba Ooki is struggling to sleep in the August heat at the diving club's summer camp. She gets out of bed and goes to buy a drink from the vending machine. What is supposed to be a quick trip becomes confusing when she gets lost in a seemingly endless looping corridor. She wakes up again; the previous trip was a dream, but she gets up and manages to get lost in the unfamiliar corridors once again. She finally manages to find the exit, and makes her way out onto the beach, where she sits on a wall and looks out to sea.
Mato Katori, who was woken up by Futaba closing the sliding door of their room, joins Futaba and sits beside her on the wall. Mato gives Futaba a drink and grabs her feet, giving her a foot massage. She tells Futaba that when she's not able to fall asleep because her brain is in overdrive she should massage her feet to give herself some rest. Futaba relaxes a little, and the two talk about the training camp.
Futaba tells Mato that she's realised that it's like there are two sides to her - the person overjoyed to have completed the navigational training, and the person terrified of the idea of night diving. She reasons that it must be because she's useless that she'll always wake up too fast from a "good dream" - whenever something good happens to her she'll always get depressed again soon after.
Mato tells her that it's such a waste to consider bad moments reality, but the good moments dreams - the good moments are just as real as the bad ones. Mato tells her that believing that good moments are dreams you'll wake up from soon is ending that good feeling prematurely through self-sabotage. She tells Futaba that good moments should be accepted as reality too, and that it might help give her strength if she sees bad moments as just bad dreams. The sun rises.