In December 9, 2012, Core Contents Media released the first teaser photo for "It's Over" for their debut album Superior Speed.

Two music videos were released for the song "슬플약속 (That's My Fault)" featuring Davichi's Kang Minkyung; a dance version and a drama version featuring Park Bo-young, A Pink's Naeun, Ji Chang-wook, and Ha Seok-jin.

"슬플약속 (That's My Fault)" is a minor medium tempo song themed Mandorin and each member's rap works along well with it.

[3] The filming started this morning on the 15th, and will continue on for two more days under the direction of director Cha Eun Taek, with a special appearance by Kim Young Ho.

A young man, Chang-wook who fell in love with Bo-young when they met at the time of the incident, but he was feuding with her brother, Seok-jin.