Season 1
Suddenly 4 People in the Family?!
Miyu Kōzuki's parents had moved to the United States to work for NASA. Miyu has been told she is to live with her parents' old friend. She arrives, and it turns out to be a Buddhist temple. She meets her parents' friend, the temple monk, Hoshou Saionji, and his teenaged son, Kanata. The monk soon leaves for India for religious training, leaving Miyu behind with Kanata. Shortly after, a UFO flies into the house, and inside were an alien baby called Ruu and a "sitter-pet" called Wanya. They all then decide to live in the temple together. Kanata peeps at Miyu while she's showering, just as Miyu has seen him changing.
Ruu-kun is Climbing the Chimney
It was Miyu's first day at her new school. She finds out that Kanata has a fan club, and he is the class president. Miyu meets Christine Hanakomachi, a half-French girl who fancies Kanata. During class, Miyu spots Ruu flying outside. Kanata and Miyu chase after Ruu. Ruu ends up climbing a chimney, forcing Kanata and Miyu to climb it too.
Chris Drops By
Chris and her friends came by Kanata's house to have a welcome party for Miyu. But their home turned out to be a disaster. They needed to take down floating items and hide Ruu and Wanya from their guests. Chris misunderstands Miyu and Kanata's relationship, after they discover Ruu.
Momoka and the Necklace
Kanata and Miyu both go out with their friends. Before Miyu leaves, she notices that her necklace is missing. A crow has taken it. But 3 year-old Momoka chases the crow away and retrieves the necklace. While shopping for dinner, Wanya loses Ruu. Ruu finds Momoka with the necklace. They both are together, when finally Kanata and Miyu find Momoka and Ruu. Momoka starts referring to Ruu as her boyfriend.
Miyu's Awful Cuisine
Mama Comes Over on Mother's Day
Ruu-kun, Popular at School
Ruu-kun's Acting Debut
A Date in the Park Between Cousins
Playing with Spaced-Out Santa
June, on Father's Day ... Papa Comes
The Mysterious Boy, Yaboshi Seiya
The Mysterious Planet Sharaku
Help! Transforming Wanya
Mikan Ran Away, Saionji!
Ocean and the Lovers' Tree
India's treasure is SAIONJI?
Momoka's Passport
The Mysterious Home is Miyu's Real House?
The Off-season Home Visit
Principal, Monkichi Reunite
The Hike of Fear
Everyone, Gather at Saionji's
The Blackout Halloween
Ruu-kun and the Department Store
Yaboshi Saiya's Warning
A Correspondence with Ruu's Parents
Sister Comes to Saionji
Nanami and the Mysterious Tsukemonoishi
Wanya Wanya
The First Christmas with Saionji
Chris, Ski, Mansion
Kanata's Childhood Friend
Kanata's Promised Date
Bye Bye Wanya
The Heiomachi Onsen Excursion
Miyu's Idol Debut
Ruu-kun Has Multiplied
All 100 Ruu-kuns, Gather!
Kanata's Rival Appears?
Kanata and Nozomu's Showdown
Where is Okame-chan?
The Family Assembles at Saionji
Koinobori Aren't Scary!
Cinderella Inside the Book
Chris and the White Whale
Miyu and Mini-Miyu Go to School
Santa and Kanata's Weird Pot
Mizuno-sensei's Mysterious Trip
Stop it, Lazy Wanya
Mika-san's Mysterious Promise
Saionji's Ghost stories and the Mysterious Koishi Stones
Miyu and Kanata Go to America
Everyone but Santa goes to America
The Weird Object That Seiya Left Behind
Mecha Wanya Attacks!
Nozomu and His World of Dream
Our Pet is Number One
Peppo, Ruu, and Wanya
Mikan's Work Place is the Saionji
Miyu and Kanata's First Kiss
Nagging at the Saionji Temple
Spooky Mountain Villa
Meeting a Penpal
Inventions are so Boring
A Friend, a Rival, a Competitor
Teru Arrives From Planet
Bowmeow Versus Mister
Ousted Guava Falls in Love
Momoka’s Christmas
The Seven Gods of Fortune
The Same Kimono as Miyu
Miyu and Little Boy Kanata
Goodbye Evil Gang
Valentine’s Day in Heiomachi
Ruu in the Lead Role at the Cultural Festival
On the Night of the Full Moon
See You Again