姐的幸福下落不明
[jiĕ de xìng fú xià luò bù míng]
This translates to 'The Disappearance of My (Sister's) Happiness'. Here, happiness seems lost and nowhere to be found, signifying the longing for lost joy or peace. '姐' typically refers to 'elder sister,' which sometimes may just be a self-proclaimed mature style for girls.