This episode largely takes place in a flashback that Cruz/Yamada is inferred to be telling after Seto and Solva save Adam Blade from the Pretty Girl Squad in Shelter #3.
Somewhere in the western area of Black Spot, Adam Blade and Seto take a bus ride to a village. Along the way, Adam tries talking to a little girl (Solva), but Seto smacks him with her gigantic sword. Suddenly, the bus is attacked by two strong guys, one of them holds a dart at Solva's neck, but Seto uses the power of her sword to send them both flying. Solva thanks them for their help, and somehow knows their names. She takes them to her village, saying that they have been attacked by bandits and asked "The Guild" for help.
Adam's on board because Solva is a cute loli, but Seto wants money, and Solva says that there's a treasure if she completes the job. However, both Adam and Seto accidentally drink drugged tea and find themselves taken hostage by the same two guys from before, along with a girl Needless who seems to be able to control both fire and ice. She offers to hire them as henchmen, and when they refuse she locks them up in a cell.
Solva and the villagers rush into the house and bust them out, and in a dramatic fight sequence Seto throws her blade into the girl's chair, piercing it. After the girl is unable to attack them, Seto announces that the girl was never a Needless, but simply faked it with a device installed on the back of her chair. Solva asks Seto to finish the job and kill the girl and her bodyguards, but Seto attacks Solva instead, claiming that Solva and her village were the real bandits. Not only did they have the advantage of numbers, but Solva somehow knew their names before without ever meeting them.
Solva reveals her power of magnetism to rip Seto's sword out of her hands, but Seto uses her power anyway, as the sword was not needed for the Needless. The two of them fight each other, magnetism vs. gravity, and Solva appears to be slightly stronger until Adam Blade steps in and memorizes her attack. Then both he and Seto use their combined strength to defeat Solva. The girl from before thanks Seto and Adam, and reveals her own treasure: a small plot of land where sunflowers are growing.
As the two prepare to leave, Solva reappears and asks to join up with them. She reasons that with their help, she will be able to one day rule all of Black Spot. Despite her comically-evil intentions, they decide to let her travel with them. As Cruz finishes his flashback, the group in the present yells "Shut up, Yamada!" as the episode ends.