Chinatown's most famous detective duo are back! Qin (Liu Haoran) arrives in New York City to attend Tang’s (Wang Baoqiang) wedding… or so he thinks. It turns out the so-called wedding is actually an international detective contest with an attractive cash prize for whomever manages to locate the missing grandson of Uncle Qi, the ‘godfather’ of Chinatown. Angry about being deceived, Qin decides to leave New York City, but the contest takes a sudden turn; Uncle Qi’s grandson has been murdered, and in a strange way. Qin joins Tang to form the “Detective Chinatown duo” and all the detectives involved try their best to solve their case.

秦風（劉昊然　飾）接到唐仁（王寶強　飾）的邀請來 紐約參加他和阿香的婚禮。豪氣逼人的唐仁迎接秦風，極盡 招搖，豈料婚禮其實是唐仁為巨額獎金而參加的「世界名偵 探大賽」，比賽的內容是尋找「唐人街教父」七叔的孫子。 受騙的秦風怒極欲走，卻被FBI探員陳英送來的訊息所吸 引，決定與唐仁再度攜手七天內再下一城偵破奇案、誓要智 取紐約唐人街……