Ep. 12: Ruri discovers a crystal radio among her grandfather's belongings and attempts to build one with friends.

12

While sorting through her grandfather's possessions, Ruri uncovers a device made of copper wires and crystals. Nagi recognizes the item as a crystal radio. Ruri, Shoko, and their new friend Aoi attempt to replicate the device but face difficulties locating the appropriate mineral for the detector. They eventually succeed by using a germanium diode, which verifies that their construction is accurate. The group finds that a nearby shrine, which holds significance for Ruri's family, provides superior signal reception for their creation.