Notorious debt collector and convicted murderer Nickie Dryden (Billy Connolly) is a man with few friends. Having served his sentence in one of Britain's toughest prisons, his remarkable transformation into a happily married man and acclaimed sculptor belies his shady history. But now Dryden's past returns to haunt him and it is time to pay his dues.

Garry Keltie (Ken Stott), the policeman responsible for Dryden's conviction, is a bitter and twisted soul, and embarks on a campaign to ensure his violent crimes are not forgotten nor forgiven. As Dryden and Keltie clash, an impressionable teenager called Flipper (Iain Robertson) steps into the breach to prove himself to Dryden, and make his own mark on the criminal world - jostling with a policeman who has stepped outside the law and the ex-criminal who cannot ignore the past.

Some debts can never be paid in full.