Bài hát: Himitsu No Tobira Kara Ai Ni Kite (Nourin Opening) - Yukari Tamura

Ai tai toki wa dou suru? Tsubasa ga are ba ii noni
Kimi ni ai tai toki wa dou suru ?
Himitsu no tobira wo knock knock!
Ii desho?

Tooi futari no kyori ga
Setsunaku te egao ni nare nai
Sonna watashi no koto mo wakatte yo
Sabishikutte chotto okocchau

Suki ni natte hontou ni yokatta to
Mainichi sasayaki tai motto ne!

Ai tai toki wa dou suru? Tsuki ni hoshi ni negau dake?
Kimi ni ai tai toki wa dou suru?
Monotarinai no yume ja
Ai tai toki wa dou suru? Tsubasa ga are ba ii noni
Kimi ni ai tai toki wa dou suru?
Himitsu no tobira o knock knock!
Ii desho?

Kimi ga watashi no naka de
Sukoshi zutsu ookiku natteta no ne
Itsumo issho jya nakya to
Negau no wa touzen desho tte yappa omocchau

Dare no sei? Setsuna sugiru mune
Yasashiku dakishime te yo motto yo!

Ii tai koto ga aru kedo koko ni inai no doushite?
Kimi ni ii tai koto ga aru kara
Hitori bocchi wa iya yo
Ii tai koto ga aru kedo heya ni dare mo inai no ne
Kimi ni ii tai koto ga aru kara
Himitsu no tobira de knock knock!
Kite yo ne!

Suki ni natte hontōni yokatta to
Mainichi sasayaki tai motto ne!

Ai tai toki wa dou suru? Tsuki ni hoshi ni negau dake?
Kimi ni ai tai toki wa dou suru?
Himitsu no tobira de knock knock !
Kite yo ne!
Ai tai toki wa dou suru? Tsubasa ga are ba ii noni
Kimi ni ai tai toki wa dou suru?
Himitsu no tobira o knock knock!
Ii desho?