Ballett Frankfurt, Sadler's Wells, London

With Artifact, created for the Ballett Frankfurt in 1984 and shown in the first half of this season, William Forsythe was still feeling his way; with Eidos: Telos (1995) he had well and truly found it. Or that's how it seemed to me, although my friend thought the exact opposite. More than any other choreographer Forsythe can fiercely split audiences or fragment the responses of a single individual. His pieces vary so much in means, style and scale you can love one and detest the next.

Even I, though, can recognise that Eidos: Telos has its wearisome moments. The twisting, bottom-jutting air-traces of the six, semi-improvising dancers in the first part, 'Self Meant to Govern', produces a disjunct visual density that doesn't sustain prolonged interest. The intermittent ear-shattering assaults by the on-stage violinist and trombonists can irritate as much as excite. But with parts two and three its terror-filled beauty really bites. The countdown of time suggested earlier by scattered clockfaces accelerates towards inevitable doom. The wires and floor lines stretched across the stage evoking musical staves and strings (Thom Willems's score refers to Stravinsky's Apollo) become a spider's web entangling its onlookers in the nightmare of Hades.

Part two is a tour de force for Dana Caspersen, an arachnid Persephone and Demeter, whose panic-stricken monologue and frantic, scrabbling body language has you staring into the earth's abyss where lies the "salt, dirt and night" of death. This is the antithesis of floating Christian afterlife, a place of wintry decay and shrivelled organic matter. Flowers are a memory recalled by a scrunched mass of cellophane, which Caspersen abruptly holds up to a light projector, its orange colour flaring into a blinding inferno and Caspersen suddenly seeming like a moth. The ball-gowned dancers, who swish and billow in courtly rhythm, are spectres, their ceremonious lines ordered, yet oddly dislocated. In their midst comes Antony Rizzi's foul Beelzebub, spouting vindictive obscenities.

By the final section, the air seems cold and still, all oxygen sucked out. Forsythe cleverly alternates ominous moments of relative quiet with sudden rips into cacophonous horror, as the action travels irreversibly to its apocalyptic finale. A master of big-scale theatrical effect, he transforms his cast into a vast machine of different moving parts, programmed for auto-destruct. A line of dancers plucks at the stretched strings in demented unison repetition. Figures begin to collapse, run and disappear, leaving a final tableau of near emptiness and your ears ringing.

This is the end, the piece seems to be saying, clearing the space for a new beginning. And this is a piece where the Frankfurt performers hit their stride as dance-theatre specialists, their imperfect classical techniques kept in the background by the drama and a contemporary movement vocabulary.