THERE'S something of playwright Bruce Norris in the teenager Thor at the centre of his Vietnam War drama Purple Heart.

The youngster is obsessed with the cheap, but harmless practical jokes sent by his late father, killed fighting in Vietnam.

But there's a darker side to his imagination, revealed by his fantasies about luring a female classmate into a deadly punji trap, filled with sharpened stakes.

Norris, whose mega hit Clybourne Park cemented his reputation, has a similar attitude towards his audiences - a playful determination to lure them down false avenues, tinged with a mean streak.

Watching one of his plays can be a bruising experience, thanks to his habit of constantly predicting and challenging our reactions, and Purple Heart is no difference.

Carla is drowning in other people's sympathy, and running out of place to store the casserole dishes, following the death of her husband in Vietnam.

As she struggles to come to terms with her grief, and the conflicting emotions towards a man who beat and bullied her, a mysterious stranger appears.

The war veteran, who lost his right hand in action, initially proves a welcome distraction from the oppressive understanding of her mother-in-law.

But, with echoes of An Inspector Calls, she soon begins to question whether he's everything he seems.

Written in 2001, Purple Heart is making its UK bow just weeks before Norris' latest play The Low Road opens at the Royal Court, but it's an impressively mature work.

It tackles subjects including post-traumatic stress disorder, rape and war crimes with a refreshingly light touch, using a sometimes childish line of questioning to challenge the status quo and drive at deeper truths.

Christopher Evan Welch is particularly impressive as the mysterious war veteran Purdy, bringing an unsettling, childlike intensity to everything he does.

It may have taken more than a decade to reach these shores, but this is Norris at his playful and devastating best.