Futaba takes the underwater navigation tutorial but is brought crashing back to reality by the realization that she may be holding Hikari back - but is able to successfully complete it after she remembers all the lessons she had been taught by her friends. After watching the twins go on a night time dive, Futaba wrestles with the feeling that she may be holding Hikari back.
While Futaba is away for a memorial at her country home, Hikari befriends a girl by the sea who is fascinated by a mother octopus guarding her young - Futaba is determined to befriend her. Meanwhile, Futaba works hard as a volunteer helping to set up the local fireworks festival, working hard enough to earn front row seats in the VIP section of the festival for her friends.
After helping out at Kino's beach house during a lunch rush, Futaba decides to return there the next day while Hikari goes scuba diving with the others. While there, Hikari accidentally goes into an outdoor hot spring without her bikini top, putting her at risk of being exposed before the other girls come to save her. Later, after Hikari holds a barbecue party for everyone, Futaba worries about what she'd do if she has to part ways with Hikari, but Hikari encourages her to enjoy every moment they spend together.