"Lady Audley's Secret," the newest installment in the "Mystery!" franchise was not a classy book, and Lady Audley is not a classy character, although she could play the role. Rather than a surprising thriller, or even a smartly-crafted mystery, what comes across here is a prettily photographed but disappointingly flat telling of a potboiler novel.

Those Brits can make even the most sensational work seem classy when they put it on the screen. But in the case of “Lady Audley’s Secret,” the newest installment in the “Mystery!” franchise, such seeming improvements prove to be an odd weakness. This was not a classy book, and Lady Audley is not a classy character, although she could play the role. Rather than a surprising thriller, or even a smartly-crafted mystery, what comes across here is a prettily photographed but disappointingly flat telling of a potboiler novel.

In the very first scene of the film, Lucy (Neve McIntosh), governess to Sir Michael Audley’s daughter Alicia (Juliette Caton), takes a large leap up in the world when her employer (Kenneth Cranham) proposes. After the marriage, though, it isn’t long before Lucy’s elaborate past begins to catch up with her. It turns out that she was married previously, and even had a child; her husband, George Talboys, has been looking for her for years. Just Lucy’s luck, it turns out that George is best friends with Robert, Sir Michael’s nephew and Alicia’s paramour.

Lucy does all she can to avoid George (Jamie Bamber) when he comes to visit, but the secret will out, and soon George disappears from the scene. As he investigates his friend’s whereabouts, Robert Audley (Steven Mackintosh) begins to become exceedingly suspicious of — and attracted to — the beautiful and possibly very dangerous Lady Audley.

The 1862 novel by Mary Elizabeth Braddon is not great art, but it perhaps should be given credit for inspiring some. An enormous bestseller in its day, the book sparked the popularity of “sensation” novels, primarily with a female character at the center, known as “the woman with a past.”

These stories of wayward women became so common and formulaic that some of the greatest dramatists of the late 19th century, including Ibsen, Wilde and Shaw, felt compelled to take a turn, crafting masterpieces that were indirect descendants of this more sordid original.

Director Betsan Morris Evans seems to wish he were directing one of those later, layered classics, but in trying to unearth subtleties he fails to capture the shocking quality of the tale; the twists in the story seem almost irrelevant.

Perhaps above all, Neve McIntosh is simply too innocent as Lady Audley — the story has her taking an active role in covering up her sins, but somehow the character always seems passive rather than manipulative.

Steven Mackintosh as Robert also leaves too much to subtext. This adaptation tries to find nuance where there should be melodrama.

Mystery!: Lady Audley's Secret

PBS; Thurs. March 23, 9 p.m.

Production

Shot in Essex, England by WGBH/Boston. Executive producer (WGBH), Rebecca Eaton; producers, Anne-Marie Casey, Jane Wellesley; director, Betsan Morris Evans; writer, Donal Hounam, based on the novel by Mary Elizabeth Braddon.

Crew

Camera, Julian Court; editor, Jeremy Gibbs; production design, Caroline Greville-Morris; music, Paul Carr; casting, Marily Johnson. 90 MINS.

Cast

Lucy, Lady Audley - Neve McIntosh Robert Audley - Steven Mackintosh Sir Michael Audley - Kenneth Cranham Alicia Audley - Juliette Caton George Talboys - Jamie Bamber Phoebe - Melanie Clark Pullen Luke Marks - Paul Swinnerton Host: Diana Rigg
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