A Step Into the Past (2001)

The main character, Hong Siu Lung (Louis Koo), is a special agent in Hong Kong (21st century). During a exhibition of the First Emperor's Terracotta Army, Hong's colleague mentions that one of the warriors look much alike to Hong. A while later, a rich businessman named Lee Siu-Chiu is held hostage by a madman. Hong rescues him. Impressed by Hong, Lee Siu-Chiu and Doctor Wu Yau recruits him for a secret time traveling mission. Hong only agrees because he sees this as a chance to save his failed relationship with Chun Ching. They plan to send Hong 2,000 years back to the Qin Dynasty when Ying Ching becomes emperor so Hong can document that event with a digital camera. However, an error occurred, and Hong is actually sent back 3 years earlier than the designated time. To return back to the future where he belongs, Hong has to make a perilous journey across ancient China to activate a device at a specific time and place. Hong must not change the course of history or it can result in catastrophe.