Hattie Naylor's adaptation of Sarah Waters' novel The Night Watch is ingenious, intelligent and true to the original, but is most satisfactory as a prompt to tackling the novel itself. To reduce 500 pages to 110 minutes of stage time and still retain the essential narrative structure of the original is skilful indeed, but it comes at a price in terms of layers of characterisation.

The play follows the novel in proceeding backwards in time with scenes in 1947, 1944 and 1941. In 1947 Kay Langrish, described as "the perfect gentleman", is clearly a broken woman, with the cinema her main friend. She is moved by the return of a ring to her by Viv Pearce who works in a sort of dating agency with Helen Ginever. Viv's brother Duncan lives with a much older man, Mr Mundy, and is clearly disturbed by the arrival of a figure from his past, Robert Fraser. Helen meanwhile becomes obsessively jealous of her lover Julia's relationships with other women.

Act one is thus something of a puzzle: who are these people and what is the significance of this or that action? Then just before the interval the forlorn Kay is transformed into a dynamic ambulance driver of 1944 and act two provides the answers. Kay, Julia and Helen are entangled in a web of changing sexual relationships; Viv and Duncan endure their separate traumas; the significance of Mr Mundy and Robert Fraser becomes apparent.

It is all cleverly done in Rebecca Gatward's stylish production, with a uniformly excellent cast of eight. Jodie McNee is outstanding as Kay, compelling attention even when doing almost nothing in act one. Thalissa Teixeira is sympathetic and convincing as Viv, the only straight female leading character.

Kelly Hotten finds her way skilfully through the different roles Helen plays though the years, Joe Jameson never overplays the sufferings of Duncan, a character born to trouble, and Gbemisola Ikumelo is amusingly expansive as Mickey, Kay's friend from the ambulance service.

Christopher Ettridge memorably doubles the comic role of a dissatisfied customer at the agency with the stoically arthritic Mundy. Lucy Briggs-Owen adds a fervent Christian Science doctor to her main role as the joy-seeking Julia, while Ben Addis, a rather creepy Fraser, is refreshingly open and decent as a Welsh ambulance driver.

Staging is atmospheric and impressionistic, with simultaneous and overlapping scenes. Even before the start the cast, in collar-less shirts, braces and drab trousers, slowly continue dressing while rotating round Georgia Lowe's circular design which revolves, often in two different directions, throughout the evening. Dan Jones' sound plot is full of explosions, air raid sirens, flashes of dialogue and cries from the ashes. Is it all trying a bit too hard to fill the gap left by depth of characterisation?

Running time: 2 hours 10 minutes (including interval).

The Night Watch runs at the Royal Exchange Manchester until 18 June.