This extraordinary, beautiful piece of theatre, the latest Simon McBurney has created and directed for his Complicite Company, is inspired by mathematics and metaphysics. The central focus is on real-life people: a 26-year-old Brahmin clerk, Srinivasa Ramanujan working in Madras, and the Cambridge mathematician Godfrey Hardy who corresponded with him and realised he was dealing with a visionary mathematical genius.

It is hard to imagine a more daunting theatrical subject. McBurney has, though, a flair for risky creative leaps in the dark and despite its cerebral cargo A Disappearing Number is freighted by an attractive, brooding romanticism.

This superlatively acted production captures minds and hearts. Its dazzling stage-craft whisks us with cinematic speediness between England and India, between the early 20th century and the 21st. The sense is of being caught in a linear-defying dreamscape. A montage of video-film images - from an Indian river in dusky black and white to a Cambridge college - together with an aural score of recorded voices, dramatic sounds, outbursts of music from John Adams to Victor Silvester, shifts of lighting and backcloth of numerals floating like cells under a microscope, all enhance that impression. We are never required to understand what is a mathematical proof or why there are many types of infinitity.

For McBurney broods more about life's higher purposes than higher mathematics. He presents two mathematical narratives that run in contrasted parallel. Saskia Reeves's dowdy, fortyish, contemporary lecturer in mathematics is touchingly surprised by eros in the unlikely shape of a smart, Indian-American financier and marries her. Hardy coaxes the innocent, unworldly Ramanujan briefly to a racist England and Cambridge for East-West mathematical collaboration.

The play's title is poignantly telephonic, since it refers to the contemporary lecturer's telephone number, one her husbands wants to retain: both 20th and 21st century mathematicians die tragically young. Their deaths raise questions about the purpose of life.

McBurney describes mathematics as being about enduring ideas, about the making of patterns - those discovered by Ramanujan are now reckoned crucial to understanding the string theory that physicists believe may explain the Universe. Ramanujan triumphs posthumously.

Miss Reeves's mathematician, in a fine, romantic vision of her bones mingled with those of her husband, discovers another, humbler pattern of lovers at first separated by death, but transcendent when in graves united.

• Until 6 Oct (0845 120 7550).