Letty has been captured; just when he thinks he's doomed to be turned into cool gear, he finds out how nice the gladiatorial life can be; with a bunch of new friends all around him, he doesn't know if he will ever want to leave prison.
When a pair of leprechauns lose their home, it's up to Pip to save the day; Dearia shares a tale from his childhood, his apprenticeship to a wise serpent, and the moment his passion for real estate was ignited.
A monster hunter and his trusty companion are hot on the red dragon's trail; Letty and Dearia stumble upon a demanding princess who also needs a new home.
The team prepares for its first tournament; when Yuni panics, Haijima saves the game but insults Yuni, leading him to tell the rest of the team about his past.
At Seiin High School, Yuni and Haijima both join the volleyball team, but Haijima stops coming; the captain and vice-captain convince Haijima to return even with Yuni on the team.
At Samezuka Academy, the hot-blooded practices continue ahead of regionals; meanwhile, the Iwatobi Swim Club trains diligently each day until sundown; though Amakata-sensei is concerned, Haruka and the boys insist they want to practice.
As the tournament continues, Sousuke tells Rin about how he's past their years of separation; Rin is concerned at Sousuke's nonchalant attitude toward certain things and tries to speak his mind.
The Iwatobi Swim Club continues their training; however, signs of confusion seem to keep surfacing in Haruka's swimming; Makoto and the others are worried about him, but try to continue acting cheerfully, as though nothing was wrong.
Upon Rin's invitation, Haruka finds himself venturing to a certain country; knowing that Haruka has hit a wall worrying about his future, Rin opens up and speaks to him about his own thoughts and feelings.
At last, the big robot expo in Tokyo gets underway; the diminished Robot Research Club finally gets to show off its robot, and Akiho finally gets the chance to see her sister again.
Chaos erupts at the Robot Expo as Misaki starts destroying robots left and right; slowly, but surely, Kaito begins to learn the truth behind everything.
Working through the night, the Robot Research Club members and the throngs of volunteers finish modifying GunBuild-1 before the Black Hole Bomb can be launched; the club members also devise a number of strategies for the upcoming final battle.