Invisible Target director Benny Chan draws inspiration from the 2004 English-language thriller Cellular for this tense tale of a self-centered debt-collector who risks his life to rescue a desperate mother and her young daughter. Bob (Louis Koo) is a single father with a dead-end job as a debt collector. Essentially an easygoing, helpful guy, Bob tries in earnest to perform well in his new position while dealing attempting to clean up his act so his sister won't move to China with his son. He's making progress too, so when he receives a frantic phone call from a woman named Grace who claims she's been kidnapped, he reports the disturbing call to the local police. Although the detective on duty dismisses the call as a prank, Bob's instincts tell him differently and he quickly makes the decision to investigate. Realizing that he's the only personal capable of saving Grace and her daughter from a painful demise, Bob prepares to risk everything - including his own family - in order to save two people he's never met, and may not even exist.