Heroin addict Mark Renton stumbles through bad ideas and sobriety attempts with his unreliable friends -- Sick Boy, Begbie, Spud and Tommy. He also has an underage girlfriend, Diane, along for the ride. After cleaning up and moving from Edinburgh to London, Mark finds he can't escape the life he left behind when Begbie shows up at his front door on the lam, and a scheming Sick Boy follows.

London publicist Helen, effortlessly slides between parallel storylines that show what happens when she does or does not catch a train back to her apartment. Love. Romantic entanglements. Deception. Trust. Friendship. Comedy. All come into focus as the two stories shift back and forth, overlap and surprisingly converge.