Daniel Craig's character buys, cuts, and sells coke. Although he works with gangsters, he considers himself to be a business man. He does not believe in gun use and lets his associates Morty (George Harris) and Genen (Colm Meany) work the violent side of the business.
Although he wants to retire at a young age, the protagonist is asked by his boss, Jimmy to find the missing daughter of his associate, Eddie Temple, played by the wonderful Michael Gambon (Dumbledore in the Harry Potter movies). He also needs to organize an ecstasy deal involving drugs stolen from Serbians. Soon, Craig's character gets way in over his head as he has always believed to "make a plan and stick with it" and "to quit while you're ahead," which could be considered his two personal mottos.
The movie has a good story and it is interesting to see Craig in a role where he is not a violent character, but he has to deal with those who are. I think it is one of his best roles and it is the role that got him the position of 007. Colm Meany and Michael Gambon both give good performances too. Ben Wishaw, who plays Q in "Skyfall" gives a really good performance as the nephew of a low-level gangster. The plot is complicated as it has many layers, justifying the title "Layer Cake," which also refers to the levels in the criminal underworld. The movie has great music and is well shot and what I think is one of the most memorable endings in film.
Here is the opening monologue from the movie.