My Cousin Rachel Sam Claflin, Rachel Weisz, Holliday Grainger. Directed by Roger Michell. Rated PG-13. Opens Friday in select theaters.

Based on a novel by Daphne du Maurier, whose work has provided source material for suspense classics including Rebecca, The Birds and Don’t Look Now, My Cousin Rachel has all the necessary ingredients for a great Gothic potboiler, but writer-director Roger Michell rarely gets it above lukewarm. Alfred Hitchcock probably could have done wonders with this material (which was previously made into a 1952 film starring Richard Burton and Olivia de Havilland), but Michell, a journeyman director whose best-known work is in comedy (Notting Hill, Morning Glory), doesn’t have the same command of tension and intrigue.

Michell also has a fairly bland leading man in Sam Claflin, who plays Philip Ashley, a 19th-century orphan raised on an English country estate by his older cousin Ambrose. While away in Italy convalescing from a long illness, Ambrose meets and marries a distant cousin, Rachel, but his letters to Philip turn from romantic to paranoid, with accusations that Rachel has harmed him. Following Ambrose’s sudden death, allegedly from a brain tumor, the mysterious Rachel (Rachel Weisz) comes to live at the Ashley estate, and Philip falls under her spell.

Whether Rachel is a devious, possibly murderous schemer or just a free spirit who flouts the moral code of her era is the movie’s central question, and Philip’s growing suspicion and paranoia, mixed with lust and admiration, drive him slowly mad. Claflin isn’t quite up to the task of conveying Philip’s anguish, though, and the movie is more of a sedate period drama than a slowly escalating thriller. Weisz is a more intriguing screen presence, but the need to keep Rachel inscrutable means she only has a limited range to work with. Holliday Grainger, as the long-pining family friend Philip is clearly meant to be with, ends up showing more passion than the movie’s central lovers.

As Philip becomes consumed by his obsession with Rachel, the movie should mirror his madness, but it remains restrained and composed all the way through its anticlimactic ending. Rather than leave the audience with haunting unanswered questions, Michell gives the impression that there was never much worth asking in the first place.