Assassin/Hitman Lynch has just arrived in London on his way to kill a Mr. Fish. He stops a thief from stealing a cell phone from a Spanish girl who he immediately falls in love with. The girl is pregnant and about to leave her boyfriend, a hi-tech locksmith named Abe Klein. And it was his cell phone.
Lynch doesn't act on his infatuation immediately, but he decides he must when he discovers his cell phone accidentally was switched when he stopped the thief. Cut off from his employer's instructions, Lynch goes on a manic rampage across London in an attempt to find his phone and steal the girl he loves away from Abe.
Meanwhile Abe has received a call directing him to a locker, containing a gun and a lot of money. Mistaking the call for a lock-opening job, he and his pothead friend Jimi Mistry suddenly find themselves in a position to pay off a debt to porn king Danny Devine, and maybe make more money by warning Lynch's target Mr. Fish.
They soon find themselves pursued by Lynch, who in turn is being pursued by the hitman Dragan, who his employers hired to silence Lynch because he didn't sound like himself on the phone.
A wacky circle of misunderstandings, kidnappings and coincidences drives this story to a climax nobody sees coming.