This song has two versions. This is the one heard in the OVA before the credits.
Ame ga agattara sore ga aizu da yo
Rain falls, that's a signal indeed
Fushigi no mori ya oka wo koete
An strange leakage after the hill
Tokoton minna de sagasu no da
Let's all search throughly~noda
Kitto densetsu no niji ni aeru yo ne
For sure, we will find the rainbow of the legend
Kirakira no aachi wo wataru no da
We will cross the luminous arch~noda
Niji no mukou ni ha naniga mieru no ka na
What we will find at the other side?
Nanairo no shiawase ga matteru no da
Let's await the joy of the seven colors~noda
Aka to orenji to kiiro midori ao
Red, Orange, Yellow, Green, Blue
Aiiro to murasaki chanto mieta?
Indigo, Violet, did you see them?
Niji no mukou kara dareka yonderu yo
Beyond the rainbow someone is thinking
Genki yoku te wo furou niji wo manete
As nicely hands, Rainbow will last always young
Full version
Ame ga agattara sore ga aizu da yo
Rain falls, that's a signal indeed
Fushigi no mori ya oka wo koete
An strange leakage after the hill
Tokoton minna de sagasu no da
Let's all search thoroughly~noda
Kitto densetsu no niji ni aeru yo ne
For sure, we will find the rainbow of the legend
Kirakira no aachi wo wataru no da
We will cross the luminous arch~noda
Niji no mukou ni wa naniga mieru no ka na
What we will find at the other side?
Nanairo no shiawase ga matteru no da
Let's await the joy of the seven colors~noda
Machi no achikochi ga ippai hikatteru
There are towns here and there, shining a lot
Niji ha doushite dekiru no ka na?
How the rainbow could do it?
Tottoko himitsu wo sagasu no da
Let's search the secret~noda
Aka to orenji to kiiro midori ao
Red, Orange, Yellow, Green, Blue
Aiiro to murasaki chanto mieta?
Indigo, Violet, did you see them?
Niji no fumoto ni wa naniga aru no ka na
Would the base of the rainbow exist?
Yumeiro no gochisou ga matteru no da
A dream feast is waiting us~noda
Aozora massugu niji no kuni made tondeyukou
The blue sky is direct to the Rainbow Land who is waiting us!
Kitto densetsu no niji ni aeru yo ne
For sure, we will find the rainbow of the legend
Te wo tsunagi nakayoku wataru no da
Let's cross with our hands held friendly~noda
Shiroku hikaru kumo minna waratteru
Let's go to the castle shining clouds
Nanairo no shiawase wa kimi no egao
The joy of the seven colors is the Prince's smile
Aka to orenji to kiiro midori ao
Red, Orange, Yellow, Green, Blue
Aiiro to murasaki chanto mieta?
Indigo, Violet, did you see them?
Niji no mukou kara dareka yonderu yo
Beyond the rainbow someone is thinking
Genki yoku te wo furou niji wo manete
As nicely hands, Rainbow will last always young
