O!RUL8,2? is the first extended play by South Korean boy bandBTS. It was released on September 11, 2013 as the second album after 2 Cool 4 Skool. The album consists of ten tracks, with "N.O" (also known as "No Offense") as the lead single. The group later promoted "Attack On Bangtan (진격의 방탄)", another track from the album.
On August 27, 2013 Big Hit Entertainment launched a countdown clock on BTS official website and uploaded a comeback trailer on August 27 on YouTube in preparation for O!RUL8,2? and comeback promotions. It featured a monologue by Rap Monster as different 3D images related to BTS floated in space before shattering into the ground and starts off with a voice-over narration that talks about how one should pursue his or her dream. Three days later, they revealed the O!RUL8,2? track list and concept photo of the album on their official Twitter account and Facebook page. They also released the design and details of the physical album, along with its photobook, photocard and poster. Big Hit Entertainment then released a special trailer for the album's concept. They later released the first teaser, revealing that "N.O" would be the lead single. On September 8, 2013, BTS dropped an audio preview prior to the actual release of the album.
The music video for the lead track, "N.O" (an acronym for "no offense"), was released on September 10, one day before the release of the album. The music video featured the members dressed in uniforms, and rebelling against their teacher in what appears to be a dystopian classroom. Their dance was choreographed by Son Sungdeuk and the music video was directed by Zanybros.