It's just a guess, but I think this song is about the two star-crossed lovers who can only meet once a year on Tanabata. I really enjoyed this song too, even though it's slow paced.
Kanji:
夜空を分ける 川は遠く
二人の季節を待って 願い溢れてる
触れてみれば 切ないほど 淡い光に
頬を濡らしたひとしずくは 胸に溶けて
空よ 忘れないで 流れる星粒を 見守って
川を 越えて行くから 今宵もまた 夢で逢えるように
そっとおやすみ
月夜に霞む 雲が隠す
浮かべたあの約束は 儚く揺れてる
すくい上げた ひとかけらの 笑顔の記憶
消える前に放つ煌めき 胸に灯せ
夜よ 終わらないで 消える星粒を 見送って
もしも 叶うのならば 二人がまた 巡り逢えるように
空よ 忘れないで 流れる星粒を 見守って
川を 越えて行くから 今宵もまた 夢で逢えるように
そっとおやすみ
Romanji:
Yozora wo wakeru Kawa wa tooku
Futari no kisetsu wo matte Negai afureteru
Furete mireba Setsunai hodo Awai hikari ni
Hoho wo nurashita hito shizuku wa Mune ni tokete
Sora yo Wasurenai de Nagareru hoshi tsubu wo Mimamotte
Kawa wo Koete yuku kara Koyoi mo mata Yume de aeru you ni
Sotto oyasumi
Tsukiyo ni kasumu Kumo ga kakusu
Ukabeta ano yakusoku wa Hakanaku yureteru
Sukui ageta Hito kakera no Egao no kioku
Kieru mae ni hanatsu kirameki Mune ni tomose
Yoru yo Owaranai de Kieru hoshi tsubu wo Miokutte
Moshimo Kanau no naraba Futari ga mata Meguri aeru you ni
Sora yo Wasurenai de Nagareru hoshi tsubu wo Mimamotte
Kawa wo Koete yuku kara Koyoi mo mata Yume de aeru you ni
Sotto oyasumi
English:
The distant river of stars divides the night sky
We're waiting for a season of our own, brimming with hopes and desires
When I try to touch it, the light grows so faint, it's sad
The single tear that wets my cheek melts my frozen heart
The sky, please don't forget Watch over the shooting stars
Since it passes over the river of stars, tonight I hope we'll be able to meet in our dreams
I gently say “good night”
On a moonlit night, it grows hazy and the clouds hide the stars from our sight
That promise came to mind seems to waver faintly
I scooped up a broken piece of a memory of your smile
The glimmer it gives off before disappearing, it lights a flame in my heart
The night, please don't end See off the vanishing stardust until it's gone
If it could come true, then I hope we'll meet again someday
The sky, please don't forget Watch over the shooting stars
Since it passes over the river of stars, tonight I hope we'll be able to meet in our dreams
I gently say “good night”
<3