用英语介绍一下《无间道》（60字左右）

Infernal Affairs is about a cop named Yan (Tony Leung) who goes deep undercover into the Triad, and Triad member Ming (Andy Lau), who infiltrates the police department. Each mole was planted by the rival organization to gain an advantage in intelligence over the other side. The more the moles become involved in their undercover lives, the more issues they have to cope with.

The film begins, after Yan and Ming converse at a hi-fi store where Yan works without knowing who each other is. A deal between Sam (Eric Tsang) and a Thai cocaine dealer is interrupted by Superintendent Wong (Anthony Wong) and his team due to Yan's tip-off using Morse Code. Ming alerted Sam of the bust with enough time for Sam to order his minions to dispose of the cocaine so the police would not have any real evidence on their hands. Now Wong and Sam realize that they each have moles within their respective organizations, putting them in a race against time to root out the other mole.