Terry Johnson has a superb track record of presenting on stage obliquely rewarding glimpses of the imagined lives of the famous, notably from the entertainment world. Cleo, Camping, Emmanuelle and Dick was a funny, convincing and ultimately moving look at the lives of Carry On stars, Insignificance focussed on the unhistorical meeting of Marilyn Monroe, Joe DiMaggio, Joseph McCarthy and Albert Einstein, and so on. Hitchcock Blonde is a later winner from the same stable, but proves a sad disappointment in Natalie Abrahami’s production at Hull Truck.

Neither direction, acting nor (in some cases) diction is clear enough to involve the audience in a narrative with deliberately built-in mysteries and loose ends: mysteries – and detecting mysteries – are not fun when your main problem is making sense of the characters and situation. Alex is a lecturer in Film Studies who has acquired early previously unknown footage shot by Alfred Hitchcock. He persuades his troubled student Nicola to accompany him to his holiday villa to view, assess and catalogue the film – he wants to seduce her, but does he love her as much as he does Alfred Hitchcock? Meanwhile these scenes are cross-cut with scenes of Hitch in Hollywood indulging himself on Dover sole and the company of the latest of his notorious blonde protégées, this one with a dark secret!

One problem with the production is that it is impossible to empathise with either Alex or Nicola at any time. Nigel Hastings copes well with the fact that many of his lines read like chunks of essays, rather better than Augustina Seymour deals with a log-jam of obscenities, but neither projects a personality strong enough to convince in a character full of change and contradiction. The only consistent enjoyment comes from Alexander Delamere as Hitch. He gets the best lines, full of almost Edwardian formality and a disarming literal-mindedness, and he projects them perfectly, with those strange Hitchcockian vowels. Visually he re-creates the equally strange Hitchcockian profile. Even so, his Hitch remains a caricature, a pleasing side-show, not a creepy voyeur bent on dominating blondes.

Many of the more arresting moments come courtesy of Tom Gibbons (sound) and Mark Howland (lighting), but the projected scenes do little to clarify the action. Dramatic musical underscoring fits the attempt to create cinematic rather than theatrical reality, but the performance needs to match up to that.

Hitchcock Blonde runs at the Hull truck Theatre until 16 February. For further information visit www.hulltruck.co.uk/whats-on