Eris is funny in a way most cat girls aren't, playing dumb with actual timing instead of just existing to be cute. The show knows its harem setup is disposable and leans into pure comedy instead of pretending the plot matters. You're here for a lightweight joke machine with aliens and fanservice, and it delivers exactly that without apology.
Kio Kakazu is an ordinary high school freshman in Okinawa until a cat-eared girl turns up at a memorial service for his grandfather. She calls herself Eris, says she comes from a planet called Catia, and explains that her mission is to study Earth. After his family makes her feel at home, she moves into Kio's house. Their peaceful arrangement does not last: alien-worshipping fanatics and a secretive government agency want to get their hands on her. Among those after her is Kio's childhood friend Manami Kinjou, who hopes to follow her father into the CIA. Kio ends up protecting Eris from all of them while trying to show everyone that she poses no danger to the planet. The result is a sci-fi romantic comedy with plenty of ecchi humor.
