Simon Yam and Kelly Lin star in director Johnnie To's tale of three professional pickpockets, one mysterious beauty, and the elusive key that brings them all together. It's title taken from a street slang term describing the unique dexterity needed to lift wallets and flutter away undetected, Sparrow opens as Kei and his three partners in crime gingerly fleece unsuspecting strangers on the overcrowded streets of Hong Kong. The money Kei makes from this low-level criminal endeavor is plenty enough to sustain his modest lifestyle, and being free from the restraints of a nine to five job he can spend his days aimlessly peddling through the streets on his bicycle and snapping photos on his Rolleiflex. One day, with his lens trained on the street as usual, Kei notices a gorgeous woman wander into frame. Instantly smitten, the felonious shutterbug strikes up a conversation and learns her name is Chun Lei, and that she seems to have a particularly mysterious past. Later, it becomes apparent that Chun Lei has purposefully targeted the Kei and his partners in hopes that they will help her obtain a very important key. But Chun Lei isn't the only one in search of this elusive key, because shortly thereafter a timid tycoon named Mr. Yen shows up with a suspiciously similar request.
~ Jason Buchanan, All Movie Guide