A group of bikers are joy-riding through the streets and while their leader the teenage Han Ki-su (Lee Min-ki) is tearfully berated by girlfriend Chun-shim (Kang Ye-won) for scorning her, the biker Kim Myung-shik (Kim In-kwon), who is attracted to Chun-shim, watches dolefully.

To his surprise, he finds that she is actually Chun-shim, who is still angry at how she was treated years earlier.

He offers her his helmet, unaware that it's been switched for an identical one rigged with an explosive.

Meanwhile, the police, led by Detective Seo (Ko Chang-seok) and NPCC team leader Kim (Ju Jin-mo) examine the CCTV tape in the building that exploded and believe that Ki-su could be the bomber.

The two of them start to make the deliveries while being hunted by the police and trying to figure out who is responsible for the bombings while driving between Seoul and Incheon.