Season 1

The episode starts with three members of different factions listening to a special newscast about an alien message, the first part of which has been translated to mean "coming to play". One of the members is then called to battle aboard an enemy ship. She successfully infiltrates the ship and disarms the Captain. The situation is disrupted by a UFO passing too close to both ships. When the same member comes to, the enemy captain detonates the ship. Later, during a memorial service for one of his ancestors, Kio Kakuzu finds a cat-like alien sitting at the buffet table.

Manami and Aoi watch Kio and Elis, both waiting for a good time to make their move. As they are waiting, however, Itokazu and "Beautiful Contact" jump Kio and Elis, and are about to kill both of them when Aoi disobeys orders to wait and saves Kio. She then moves to kill Elis, but Kio begs the Momiji (not knowing it is Aoi) to spare her. She obliges, but as soon as she leaves, Manami appears with CIA back-up, knocks Kio out and captures Elis, but not before Kio sees Manami's watch and knows it is her. Later, Kio confronts Manami and begs her to help him find Elis. Manami contacts Aoi for extra help, and, receiving help from his uncle, Kio blackmails Itokazu and Beautiful Contact into helping as well. Together, they succeed in breaking into the military compound where Elis has been given to the DIA, only to find that she has already broken herself out.

Elis, along with other ranking officers, negotiate with the Japanese government wearing stereotypical school swimsuits, due to misinformation on Elis' part. Upon returning to Kio's house, Manami and Aoi visit, again misinterpreting the five Catian women dressed in revealing clothing standing in Kio's living room. They state their intention to leave, since the events of the previous episode marked them as traitors to their respective factions. Elis tells them that since Kio's house is now a Catian embassy, everyone inside is protected by Catian laws, and the two girls are invited to live there as well. Later, while the robotic servants are on guard duty and Manami and Aoi are bathing together, one of the robots is abducted by members of a yet unknown faction. Manami and Aoi spring into action, rescuing the robot, although the intruders escaped by use of a stun grenade. The next morning, Manami, Aoi, and Kio are hired by Elis as official embassy employees.

The episode opens on a concert hall filled with members of Underside of Kitten Paw, a fanatic group obsessed with cats. Their leader, Antonia Morfenoss, shows pictures of Elis and declares her to be their new idol of worship. When Kio wakes up, he walks in on Elis 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 Elis will soon be going into heat, causing her to have heightened senses, and congratulates Elis on having a mating partner on her first heat, much to Manami's outrage and Kio's embarrasment. She also assigns Elis a mission to go into Tokyo and "observe the human economy, technology, and culture", which, according to Elis, means to bring back a bunch of toys and games as souvenirs.

Kio and Elis wake up inside a yacht owned by Antonia. They are soon greeted by one of Antonia's maids, who offer them trays of gourmet food. After eating, they decide to escape, but to their dismay Elis' power suit has been limited due to Elis being in heat. They are taken to a play room with Antonia who is dressed like a giant AssistDroid. Kio notes that all of the video games have been fixed to only accommodate one player, due to the maids not having the heart either to beat their master in a game nor lose intentionally. Meanwhile, Aoi and Manami visit a weapons store and stock up. While there, they ask for a motor boat and are told the only one was sold to Director Kawasaki for his upcoming film. The girls infiltrate the set and rig the boat with real weapons, but they are caught by Kawasaki, who contracts them into his film.

Aoi's frustrated by her lack of cooking ability and Manami wants to get better at handling guns. They get a chance to hone their skills in a virtual reality room on the Catian mothership - and both get to spend time with a virtual Kio.

Summer's over, class is back in session, and Kio is surprised to see that Eris and Antonia have enrolled at his school. When the gang goes on a field trip to the beach, they soon find their fun interrupted by an enemy attack!

Aoi and Manami decide to have a showdown in a nearby forest to settle their differences, but their match is cut short when they must join forces to defeat some assassins sent to take both out, the winner was therefore Manami. In the end Aoi had to pronounce Kio Kio Kun but doesn't take notice at all Manami then acted violantly.

Kio and friends are visited by Chaika, the first Assist-a-roid created by the Catians, who came to fulfill the last wish of her creators, who died while trying to reach Earth 1000 years ago.

It's Christmas and the Catians decide to prepare a special present to mankind, while Kuune, the captain of the Catian mothership pays a visit to Kio's house. However, the festivities are interrupted when the Dogisians launch an attack on them.

With the Catian ship en route of collision with Earth and Kuune out of commission, Kio is appointed the new captain of the Catian forces, and he sets with the girls to an abandoned launch base in Russia as part of their plan to aid their friends in space.

While struggling to save the Catian ship, Manami and Aoi finally manage to convey their feelings to Kio while Elis states that according to Catians' law, all three can be his lovers. After solving their situation in space, the Catians finally unveil their Christmas present to mankind; a fully functional space elevator.