This new play by Ali Taylor is a salty-sweet seascape in shades of blue, green and grey. Swirling with themes of loss, desire, abandonment and family love that is at once stifling and protecting, it is grittily poetic and thrillingly imaginative, the folkloric and fantastical eddying around its modern tale of unhappy youth. And Lisa Spirling's spare, wistful production, acted with raw immediacy, is entrancing.

It's a freezing December night in Kirkcaldy, and 18-year-old Callum and his younger brother Gussie have been to their mother's funeral. Equipped with a bag of stolen booze, they run to the beach, hoping to drink the pain away. Out in the dark water, they glimpse what looks like the floating body of a woman.

They flee, terrified, and when they return the next day to check, they find instead a seal swimming ever closer to land. And they're no longer alone on the beach; sitting on the sand is Harriet, a runaway from London who has come to Scotland in search of her absent father. As the mist rolls in like cotton wool, can this lonely, parentless trio find a way of comforting one another when the two brothers compete for Harriet's affection? And must Callum always be father to Gussie?

The Selkie myth, of enchanted seal people who shed their skins, take on human form and drag the unwary back with them to sea, becomes a potent symbol of bereavement, the peril of holding on and the agony of letting go. Taylor spells out the metaphor a little too painstakingly, but at its best the mythical lyricism is almost Ibsenite. It's a witty touch, too, that Harriet's Goth get-up should remind Gussie of vampires: an implicit parallel between the irresistible attraction she holds for his brother and the emotional blood-sucking of a mother who drained more than she nurtured.

The recriminations and revelations come rather too thick and fast in the play's final scenes, and Spirling's production has a late and unnecessary interval that impedes the momentum. But Taylor's writing is so evocative, and the performances so simply committed that the spell is unbroken. Joseph Arkley's lanky Callum is all quiet intensity, his thin body almost visibly compressed by the weight of premature responsibility. His callow attempts at chivalry towards Victoria Bavister's Harriet, a bundle of self-hatred and neediness masked by make-up and bravado, are poignantly funny. And the cheeky grin and wisecracks of Owen Whitelaw's Gussie are always a heartbeat away from dissolving into the sulks and sobs of a frightened little boy. Beneath their terse, unlovely teen argot is a siren song of grief and longing. Bewitching.

Box office: 020-7978 7040

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