Bang Bang Bang, Stella Feehily's bracing new work, erupts on to the stage with a cliff-hanger opening. We're made privy to a terrifying attack on two female human-rights investigators in their compound in the Democratic Republic of Congo. The piece then backtracks to dramatise the events leading up to this violent climax before pushing onward into its troubled aftermath.

Lifting the lid on the world of aid workers, charities and NGOs, this well-researched, empathetic and sometimes slightly contrived-seeming play focuses on Sadhbh, a 29-year-old Irish woman and seasoned Congo hand, whose mix of incurable idealism and wry, worldly ruefulness is beautifully caught by Orla Fitzgerald. When in London, she lives with her partner, Stephen (Dan Fredenburgh), a former aid worker turned consultant who wants her to concentrate on having a life and family of her own. To his dismay, though, Sadhbh is determined to return to the DRC, with Mathilde, a wide-eyed young French intern (excellent Julie Dray) in tow.

How could Stephen begrudge his lover the chance to make a vital difference by investigating alleged war crimes and gathering the testimonies of victims such as the eight-year-old Amala (Zara Brown), with her horrific story of abduction, rape and sex-enslavement? The trouble, according to him, is that there is always another Amala somewhere in the world. A missionary purpose can become a high-minded alibi for indefinitely postponing the fulfilment of duties to oneself and loved ones closer to home. And he's right about the dangers, as we witness when Sadhbh is forced to cope with the svelte intimidation of being summoned to tea by a Tutsi warlord (a drolly disconcerting Babou Cesay) who assures her that he merely does whatever is necessary to protect his people from genocide.

You feel, however, that though Sadhbh's motives are mixed and her prevarications cause pain, there is nothing cynically self-serving about our heroine's relationship with the region. This is in glaring contrast to the news men who fetch up at the drunken and druggy expat party that is one of the highlights of Max Stafford-Clark's sharp, fluent production. There's the ambitious, charmingly manipulative tyro photographer Vin (amusingly played by Jack Farthing) and Paul Hickey's hard-bitten hack, Ronan, who represents an industry that is more interested in stories about raped humanitarians than about atrocities against Congolese children.

To 5 November (020 7565 5000); then touring