A resurgent Chichester wraps up its festival season with Martin Sherman’s meaty new bio-drama of Aristotle Onassis, a piece that is less digestible than it should be.

Aristo couldn’t be accused of taking itself lightly. Hefty concepts abound: it’s based on Peter Evans’s book Nemesis and the idea of hubris presses ever more persistently as Onassis nears his death. Sherman is keen to have us see the supporting characters, arranged in a taverna-esque setting, as the helpless chorus in a Greek tragedy, yet at times when they reminded me of the local colour in Mamma Mia! Meryl Streep cartwheeling in dungarees would provide some welcome relief.

Taking the death of JFK as his starting point, Sherman concentrates on the 12 years from 1963. During this time, Onassis callously shunned Maria Callas in favour of Jackie Kennedy and came to view himself as the fulcrum upon which many world events turned. Several key figures, not least Bobby Kennedy, whom Onassis loathed, are namechecked rather than introduced, occasionally making things frustratingly hard to follow.

Everyone in Nancy Meckler’s production is saddled with a cumbersome Euro-accent except Elizabeth McGovern, whose breathy tones seem more Marilyn than Jackie. Diana Quick’s Callas has the thankless task of wafting on intermittently in floaty robes looking more and more like Medea. Robert Lindsay grandstands superbly as the mercurial megalomaniac who views people as commodities to be traded, even if he and Sherman never properly grapple with what propelled him from the poverty of post-Second World War Smyrna to the rich lists.Until 11 October (01243 781312).

Katrina Lindsay’s design is a work of real beauty, conjuring up the soft blues and whites of Greek island light. A proscenium-type frame to the stage offers Lorna Heavey’s clever video projections, where spider diagrams of Onassis’s tangled webs of international contacts are displayed as his right-hand man Costa (Julius D’Silva) attempts to unravel them. Aristo isn’t the best but it’ s an ambitious finale nonetheless.