Help Us Find This KDRAMA Song!

It should come as no surprise to most people that know us that my sister and I love KDRAMA (Korean Drama).  Inevitably, we get really hooked into the latest series and the theme music that plays while the main characters are on screen.

Also?  If you aren't watching KDRAMA, you should be.

In this case, we're watching Stairway to Heaven.  The main song that we're absolutely addicted to right now is Ave Maria by Rebecca Luker.

The problem is, we cannot. find. this. song. to. download. anywhere. Apparently, the version in the soundtrack sold on Amazon is not the same as what is on the series (and on the video above).

So that's where I need help. Does anyone know where we can get this song? I am obvs a bit leery of downloading it from some random Korean site on the internet.

Send help! These KDRAMA addicts are desperate!