This has to be the most chill zombie apocalypse in history. The song, written by Sandeul the leek-beater (not a euphemism), is a mellow tune, about being a drop of dew in the mountains.
The original video finds the boys singing in a grubby laundrette, apparently unaware of the zombie horde creeping up on them.

And if you recognise the zombies, you might have met them on a Train To Busan. Yep, these are professional and well-travelled zombies – no shamblers off the street for our boys.
“But wait!” I hear you cry. “A drop of water flowing down to the ocean – what’s that got to do with zombies?”
To which my reply is “Zombies make everything better”, which is the best you’re going to get out of me.
The song, as for most written by Sandeul, is gentle and melodic, with a lilting tune that calms and soothes, like an auditory balm for the soul. Instrumental backing is again sensibly subtle and kept to a minimum, probably because the boys produced this, as they did the rest of the Origine album.
In my never-humble opinion, the Origine album marks their transition from idols to artists, and this song is one example of that.
If you want to know what they’re singing about, the lyrics as usual contains English translation, romanisation, and hangul.