Byulyi and Yongsun had a dispute in public, ended up Yongsun getting into an car accident and died. Byulyi felt her world crumbling and never felt so hopeless and devastated in her life. Byulyi felt that it was all her fault and Yongsun's death left a big hole in her heart. After a few months of grieving over Yongsun's death, MAMAMOO is now on the verge of disbanding