Elmina's Kitchen, NT Cottesloe, London<br></br>Little Baby Nothing, Bush, London<br></br>US and Them, Hampstead, London

Crime and punishment in Dalston

The National's new artistic director, Nicholas Hytner, has scored a hat trick, with strong productions now running in all three of his auditoria. You can feel the buzz caused by the young blood he's bringing in as - hot on the heels of Jerry Springer - The Opera and his topical Henry V - we have Elmina's Kitchen. Set in London's contemporary East End, this is an assured, humorous, ultimately grim drama by Kwame Kwei-Armah (best known as Finlay the paramedic from BBC1's Casualty). It's directed by Angus Jackson, also making an impressive NT debut.

We are flies-on-the-wall in a greasy caff in Dalston's "Murder Mile" - a strip notorious for black-on-black gang warfare and gun crime. Deli (Paterson Joseph) is a British guy, with West Indian roots, who has done time but is now trying to run his establishment decently - proudly displaying a photo of his late mother over the door. His friend Digger (Shaun Parkes) is, by contrast, a hard-bitten drug dealer who mockingly calls Deli a "sissy nigger". Occasionally, the tough guy act slips, Parkes' Digger brandishing his firearms then amusingly saying "sorry" like a little boy. He's not only shielding Deli's cafe from the local protection racket, he rebukes the criminal aspirations of Deli's teenage son, Ashley (Emmanuel Idowu) - initially, anyway.

Then Anastasia (Doña Croll) saunters in off the street, flirting with Deli and cheekily asking for a job. This coincides with the murder of Deli's brother, the unwelcome return of his dad, a bust-up with Digger, and Ashley suddenly spurning his dad's values.

Kwei-Armah has a terrific ear for vibrant street talk - a mix of patois and cockney vowels that's exhilarating close-up. He simultaneously constructs an overarching narrative structure with a forceful final twist. His imagination doesn't seem startlingly theatrical, so he may go on to make his name writing TV dramas and movies. Yet Elmina's Kitchen is also a revenge tragedy for our times, with violent retribution tied in with today's complicated black culture of "respect".

This piece is particularly sharp on black machismo; on sassy women still running up against sexism; and on elders failing to nurture the good manners they expect. Jackson's production is enhanced with live music (talking drums, riti, and calypso), and his leading players are excellent, though the acting styles vary somewhat. Croll's Anastasia is lovably brassy, menacing and vulnerable. George Harris, as Deli's expansive dad, slowly reveals a chilling mean streak. And Joseph effortlessly captures Deli's gentleness and simmering anger.

Meanwhile, in Little Baby Nothing, a single mother called Anna tries to save her daughter, El, from the Devil - or maybe just from being a screwed-up teenager. I say "just", yet actually the strength of Catherine Johnson's new pseudo-satanic drama is how dark El's adolescent moods become. To begin with life is a party. While Anna is working down the pub, El (played by newcomer Alice O'Connell) is mucking around at home - on the flat roof - with her school friends, Joby and Erin. A trio of scruffy but fresh-faced Goths, they've bought a Ouija board for Erin's 15th birthday. It's a laugh, but trouble is brewing as El and Erin both fancy Joby. The more immediate spanner in the works, in El's view, is her mum, who joins in the fun uninvited, showing Erin and Joby how to contact the spirit world. Spooky stuff duly happens. El sees a figure - maybe her dad's ghost - and has a fit of hysteria. The next day Anna is terrified when El temporarily vanishes and her mobile goes dead except, Erin says, for the sound of breathing and a dog barking. The kids subsequently get into black magic while Anna's attention is distracted by Craig, the nice bloke fixing her roof.

Johnson's scenario might seem banal and corny - calling to mind TV soaps and teen movies - and the plot can feel strained, as if Grange Hill has been spliced with Dr Faustus. But disturbing games are played with audience assumptions, and generally Johnson's writing is a cut above clichés. She already proved that with the tongue-in-cheek, mega-popular ABBA musical, Mamma Mia!, about a fatherless teenage girl whose mum runs a Greek taverna. Little Baby Nothing could be hailed as a bleaker revision of that, and I've not seen pubescent girls' anti-maternal rage in such sharp focus since the film Beautiful Creatures. Occasionally, Mike Bradwell's actors demonstrate their conflicts too obviously. But Jonathan Fensom's set is terrifically downbeat - all asphalt and plastic guttering. One small, sinister gargoyle - from some tourist shop - lies casually on El's window sill. Equally subtle is the escalating monstrousness of Anna's self-centred immaturity, blithely portrayed by Suzan Sylvester. The irritation that short-circuits her motherly love is a small tragedy too, hardening O'Connell's El into a brooding, stony silence.

More dysfunctional child-parent relations feature in US and Them. In Tamsin Oglesby's new upmarket comedy, a rich American couple called Ed and Lori Marshall live in a luxurious Manhattan apartment. However, their teenage son is a surly recluse. The Marshalls eagerly befriend a middle-class British couple, an inventor named Martin and his linguist wife Charlotte who have a militantly hippy daughter in tow. After a tetchy start the kids fall for each other and run away together. But the central focus is on the adults' souring transatlantic union. As work and pleasure become entangled, the English pair are compromised by their desire for financial backing. Then, having been ripped off by a manufacturing corporation, they're dumped by the Marshalls as dishonest undesirables. This climaxes in a white-on-white, Anglo-American slanging match - moving from personal insults to incandescent, topical political rants about "Operation World Fucking Domination" etc. Oglesby is a neat, smart writer who is following in Richard Nelson's footsteps, picking holes in UK-US relations. She's also learnt a lot from Yasmina Reza about tossing some big themes and intellectual points (such as the etymology of "enmity") into a modern comedy of manners. This is a middlebrow crowd-pleaser which could easily transfer to the West End. Jennie Darnell's production, with a revolve and receding luminous frames, is slick, and her star players are on fine form. Harriet Walter's neurotic Lori contrasts with Siobhan Redmond's teasing, exasperated Charlotte. Matthew Marsh's bullish Ed is surreptitiously shifty while Hugh Bonneville's Martin is charmingly wry with a bigoted flip side. Enjoyable but inconsequential in the long run.

k.bassett@independent.co.uk

'Elmina's Kitchen': NT Cottesloe, London SE1 (020 7452 3000), in rep to 25 August; 'Little Baby Nothing': Bush, London W12 (020 8743 3388), to 21 June; 'US and Them': Hampstead, London NW3 (020 7722 9301), to 28 June