On July, 2015, it was revealed that the group would be returning with a new album the following month and that the group are ready for their Chinese promotions and that they have been starting to work on their new Chinese album sins the start of the year.
On August 3, the girls promote their comeback with the single "So Crazy". On August 12, the group started their promotions in China with the song "So Crazy (Chinese Version)" released a music video.
Commercial performance
So Good debuted at number four on the Gaon Album Chart for the week of August, 2015.
