Peribanez, Young Vic, London<br></br>Mojo Mickybo, Lyric Studio, London<br></br>Unsuspecting Susan, King's Head, London

A very peasant way of life

From the moment when a peasant bride and groom thrust their heads through a paper screen to the din of wild music, the direction of Lope de Vega's Peribanez, doesn't falter. The visual style can be a bit confusing: Che Guevara berets and combats, with charity-shop chic for the actresses, make this old-fashioned tale of vice, virtue and honour look uneasily modern. However, the moral conundrum here could have a contemporary application. War is looming, and Spain's greatest soldier, the Commander (David Harewood), has fallen madly in love with Casilda, the wife of sturdy farmer Peribanez (Michael Nardone). In other words, if David Beckham, the night before an important England game, desperately wanted to have sex with your wife, would it be your patriotic duty to let him?

This is a fabulous, riotous production: the peasants are richly eloquent, and give not a jot of ground to their supposed betters. The rhythms of their life and culture are emphasised in a marvellous musical score: there's nearly always somebody picking out a mournful tune on a guitar, or sobbing out some full-throated love song or bit of bawdy. But the ambivalent ending is problematic. Peribanez ends up committing three murders to salvage his precious reputation, and ends up looking much more like a psychopath than the salt of the earth. There are "honour" killings of women in Britain today, and we're far less likely to admire them.

In Mojo Mickybo, the distant Troubles only touch the world of two small Belfast boys as a form of entertainment. Their schoolboy antennae pick up thrilling snippets from the adults around them – is it true, one of them wants to know, that "everyone in Belfast is mad, and we're all going to get murdered in our beds?" The boys have the perfect solution, and offer the use of their den. Two hyperactive adult actors play the boys, both sets of parents, and other vivid Belfast types. Fergal McElherron is an endearing, wide-eyed Mojo, while Michael Condron takes the lead as the imaginative Mickybo (when he takes female roles he looks uncannily like Father Ted's Mrs Doyle). Their energy is awesome, but the whole play is directed at such a relentless pace that author Owen McCafferty's wordplay can get lost in the maelstrom.

Celia Imrie's pacing is expertly smooth in Unsuspecting Susan, the tale of an awfully nice middle-class mother who fusses about her dogs, worries about village gossip, enjoys bellringing and prides herself on being daring enough to accept the lead role in an amateur production of The Killing of Sister George. Pretty soon she's got more to worry about than the church flower rota. We smile knowingly at her brittle innocence when she describes her wayward son Simon's mysterious new flatmate ("just friends") and remarks how prissily neat their London flat is for two "boys". Simon's last act is to send his mother a bouquet for her opening night. Then two scene-shifters dressed as police officers turn the place over and the mood abruptly darkens. Simon, it turns out, has committed a hate crime, and we lurch from Victoria Wood territory to lurid soap-opera. Imrie just about bridges the credibility gap with her portrait of a good Christian mother who is forced to contemplate the evil she has helped to bring about. Susan is silly, snobbish and complacent; she's even, in one uncomfortable speech, vaguely anti-Semitic, but Stewart Permutt, the playwright, surely goes a bit far in suggesting that cross-stitching kneelers for the local Anglican church is somehow on a par with joining al-Qa'ida.

'Peribanez': Young Vic, London SE1 (020 7928 6363), to 7 June; 'Unsuspecting Susan': King's Head, London N1 (020 7226 1916), to 15 June