Ex-bomb disposal specialist Song Kang-Ren and his fiancée, Huang Xin, find themselves aboard a high-speed train rigged with a bomb. Simultaneously, Liu Kai, a prominent physics teacher recently embroiled in an affair scandal, boards the same train, determined to reconcile with his wife, Ting Juan, who had earlier taken a different high-speed train home in frustration. Will Song Kang-Ren manage to defuse the explosive threat in time and bring the crisis to a safe resolution?