Layer Cake

Layer cake (n): a metaphor for the murky layers of the criminal world.

Smooth-talking drug dealer X has a plan to quietly bankroll enough cash to retire before his thirtieth birthday. Operating under the polished veneer of a legitimate businessman, his mantra is to keep a low profile and run a tight operation until it's time to get out.

When kingpin Jimmy Price asks him to find the wayward daughter of a wealthy socialite who's been running around with a cokehead, he accepts the job with the promise that after this he can leave the criminal world behind with Jimmy's blessing. Oh, and he needs to find a buyer for two million ecstasy pills acquired by a crew of lowly, loud-mouth gangsters, the Yahoos.

Simple enough, until an assassin named Klaus arrives to scratch him off his list, revealing this job is much more than it seems at first.

The basis for the 2004 movie of the same name.