It's about Eunji, 8 years old girl, who is battling with brain cancer stage 4 and a big fan of Treasure. Her big sister, Y/N was ready to do anything for her little sister. all she wanted is her little sister's happiness.  -- 걱정 마, 한 번 더 뜨겁게 웃어줘 (ay, 뜨겁게, oh) 웃을 때 더 예뻐 넌 힘을 내, 우린 결국 빛날 테니 (ay, 감은 눈을 떠, oh) You're the only one treasure (Don't worry Smile at me warmly once more Ayy, with passion, oh You're prettier when you smile Cheer up