In 1987, twenty-something Wall Street banker Patrick Bateman (Bale) seems to have it all: he is handsome, successful and engaged to the beautiful Evelyn (Reese Witherspoon). However, Patrick harbours a darker side and at night indulges in a confused orgy of drugs, pornography, prostitution and murderous fantasies.

When Patrick is outshone by a rival at a board meeting, he takes out his frustration by killing a homeless man sleeping rough in the street. This sparks off a descent into violence and madness, with Patrick embarking on a bloody and random killing spree.