S1, E4: When Kio wakes up, he walks in on Eris dancing and being abnormally energetic due to having smelled silver vine spirits, an Asian plant reported to be stronger than catnip. Dr. Dyureru appears and explains that Eris will soon be going into heat, causing her to have heightened senses, and congratulates Eris on having a mating partner on her first heat, much to Manami's outrage and Kio's embarrassment. She also assigns Eris a mission to go into Tokyo and "observe the human economy, technology, and culture", which, according to Eris, means to bring back a bunch of toys and games as souvenirs. On the train back, members of Underside of Kitten Paw separate Eris and Kio from Manami and Aoi, putting them to sleep and showing the sleeping Eris live to the screaming fans of Underside of Kitten Paw.