In this episode, Ruri finds an old artifact that belonged to her grandfather and wants to figure out how it works; however, it is broken, and this time Nagi and Imari cannot help her rebuild it. Instead, she relies on her school friends to achieve her goal, an episode that teaches us about teamwork and the determination to see a plan through, while also showing the deepening friendship between Ruri and Seto, who are united by their passion for mineral research and the processes involved.