The adventures of the stoneheads, National Theatre, Lyttelton, London

A lot of curious and beautiful things come out of the sea, but the Stoneheads are not among them. To the sound of crashing surf, a couple, their son, two daughters, and son-in-law clamber over a wall toward us. Dressed only in shabby underwear, they carry their clothes in humble valises and shiver with cold. Their expressions are woebegone but mildly hopeful, and so they remain for the next 90 minutes, for they are wearing masks. There follows a performance that, for lovers of subtle intelligence, combines all the charms of puppetry and mime.

The Stoneheads' huge, head-covering masks, besides, are among the most inexpressive I've ever seen – the family resemblance announces itself in huge chins, big noses, and slitty mouths. The eyes and lips do not move, so, as the director, Toby Wilsher, says: "If the character is sad, he just tips his head.'' This gesture can be wildly effective when used by a cat that wants a daintier dinner, but it left me cold, even when employed by the insistently wistful small daughter, Pook. (Since no one speaks, the names, which appear in the program, are superfluous, but why miss a chance to crank up the cuteness level.)

Devised by the Trestle Theatre Company, the play shows the Stonehead father attempting to find work. Wearing a suit with pathetically short legs and sleeves, he is turned away from a hospital, a restaurant, and a building site. He is wrongly arrested, but escapes by pulling a policeman's helmet over his eyes, where, despite the cop's repeated tugging, it refuses to budge.

Meanwhile, having run that bit of devising into the ground, the company enact the myth of Orpheus. The Stonehead son becomes keen on a girl who dies, and, to the accompaniment of solemn music, is dragged to the Underworld by a figure that looks like an angry Howard Jacobson. Young Stonehead follows them, finds his beloved, and awakens her by strumming on what seems to be a child's toilet seat with strings.

Meanwhile, Father Stonehead meets a man whose dog lead is attached to another man, wearing red stilettos and no trousers. To this point, the show has been suitable for children, but the three now go to a brothel, where whores in scarlet lingerie bounce on them and offer an array of devices for the blasé. Disillusioned with England, and having run out of devised activities, pop returns to his family, who decide the spa is a better bet.

Last year, Trestle's modest, charming historical play, Blood and Roses, was the best thing l saw at the Edinburgh Festival. While the company deserves credit for its willingness to experiment, this abandonment of structure and authorial voice proves you can't get blood out of a Stonehead.

To 13 July (020-7452 3000)