The best reason to see this Roundabout production, an uneven adaptation of Zola’s 1867 novel by British playwright Helen Edmundson, is the spectacular set design by Beowulf Boritt. From the simple suggestion of a village cottage to a fully detailed sepulchral Paris apartment that falls from above as if to crush the characters to a skylit attic suspended in the night sky to a riverbank complete with water and rowboat, he sets the right note for this tale of limited choices, adultery, murder and guilt. His sets at least give you a focus for your attention during the glacially paced first act. As the title character, Keira Knightley doesn’t get to do much except stare soulfully during the first half hour. The always watchable Judith Light is fine as her aunt and soon-to-be mother-in-law. It is easy to understand why Therese is repelled by her sickly, spoiled cousin-then-husband Camille (Gabriel Ebert) and even easier to understand why she is magnetically attracted to his childhood chum Laurent (Matt Ryan) whom Camille runs into in Paris and, unfortunately for him, brings home to meet the family. Their sex scenes are brief and brutish.The habitués of Madame Raquin’s Thursday domino sessions — Monsieur Grivet (Jeff Still), Superintendent Michaud (David Patrick Kelly) snd his niece Suzanne (Mary Wiseman) — do not get much development. The pace picks up from late in the first act to midway through the second act. The subsequent descent into guilt and madness seemed anticlimactic. The use of many brief scenes seemed more suitable for film than the stage. Jane Greenwood’s costumes are appropriate. Keith Parham’s lighting is excellent. I did not care for the sound design and music by Josh Schmidt. The suggestions of Camille’s continued presence seemed out of a B movie. Director Evan Cabnet really should have picked up the pace a bit during the play’s early scenes. My interest lagged, but I really liked the sets. Running time: 2 hours 30 minutes including intermission. On the afternoon I attended, the performance was followed by a 25-minute Q&A with five of the actors which I enjoyed more than the play.