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.
2. 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.
3. 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.
4. 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.
6. Mama Comes Over on Mother's Day
7. Ruu-kun, Popular at School
8. Ruu-kun's Acting Debut
9. A Date in the Park Between Cousins
10. Playing with Spaced-Out Santa
11. June, on Father's Day ... Papa Comes
12. The Mysterious Boy, Yaboshi Seiya
13. The Mysterious Planet Sharaku
14. Help! Transforming Wanya
15. Mikan Ran Away, Saionji!
16. Ocean and the Lovers' Tree
17. India's treasure is SAIONJI?
19. The Mysterious Home is Miyu's Real House?
20. The Off-season Home Visit
21. Principal, Monkichi Reunite
23. Everyone, Gather at Saionji's
24. The Blackout Halloween
25. Ruu-kun and the Department Store
26. Yaboshi Saiya's Warning
27. A Correspondence with Ruu's Parents
28. Sister Comes to Saionji
29. Nanami and the Mysterious Tsukemonoishi
31. The First Christmas with Saionji
33. Kanata's Childhood Friend
34. Kanata's Promised Date
36. The Heiomachi Onsen Excursion
38. Ruu-kun Has Multiplied
39. All 100 Ruu-kuns, Gather!
40. Kanata's Rival Appears?
41. Kanata and Nozomu's Showdown
43. The Family Assembles at Saionji
44. Koinobori Aren't Scary!
45. Cinderella Inside the Book
46. Chris and the White Whale
47. Miyu and Mini-Miyu Go to School
48. Santa and Kanata's Weird Pot
49. Mizuno-sensei's Mysterious Trip
51. Mika-san's Mysterious Promise
52. Saionji's Ghost stories and the Mysterious Koishi Stones
53. Miyu and Kanata Go to America
54. Everyone but Santa goes to America
55. The Weird Object That Seiya Left Behind
57. Nozomu and His World of Dream
58. Our Pet is Number One
59. Peppo, Ruu, and Wanya
60. Mikan's Work Place is the Saionji
61. Miyu and Kanata's First Kiss
62. Nagging at the Saionji Temple
63. Spooky Mountain Villa
65. Inventions are so Boring
66. A Friend, a Rival, a Competitor
67. Teru Arrives From Planet
68. Bowmeow Versus Mister
69. Ousted Guava Falls in Love
71. The Seven Gods of Fortune
72. The Same Kimono as Miyu
73. Miyu and Little Boy Kanata
75. Valentine’s Day in Heiomachi
76. Ruu in the Lead Role at the Cultural Festival
77. On the Night of the Full Moon
