방탄소년단
What is BTS? I think the letters stand for Bangtan Sonyeondan (according to Wikipedia), but that's not really important. All you need to know is that BTS is the name of a South Korean hip-hop music group. Think "New Kids on the Block" from South Korea.
I first heard of BTS because they are my older sister's favorite music group. I eventually came to love their music, myself. It's good music for dancing! My favorite song is probably "Blood Sweat & Tears". Maybe you'll give it a listen as you head home from finding this cache.