In a Forest, Dark and Deep, Vaudeville Theatre, London

Neil LaBute's last play in the West End was called Fat Pig. By the end of In a Forest, Dark and Deep, you could be forgiven for thinking that this new 90-minute drama should be subtitled "Slender Cow". An intermittently taut two-hander, it receives its English premiere in a production by the author that stars Matthew Fox (famed for TV's Lost) and the beautiful and redoubtable Olivia Williams. They both give scorching performances that are, to my mind, a distinct cut above the material.

The piece unfolds as a cross between a psychological thriller and a slug-fest of incestuously tinged sibling rivalry. A college dean, Betty, is a blue-jeans, bluestocking to her brother Bobby's blue-collar beefcake. Needing to clear the holiday cabin she owns with her husband of the paraphernalia left by their last, hastily departed tenant, she calls on her sibling for help. Almost immediately you smell a rat, because if Betty's principal aim was really to pack up books, she might as well have glued the volumes to the shelves as recruit assistance from a brother with whom she is locked in a history of sparring intimacy.

The people on Planet LaBute are divided into the manipulators and the manipulated, and you don't need to be exceptionally smart to guess the game that is being played here, or its ulterior motive. All edgy intensity and comic political incorrectness, Fox's magnificent Bobby brilliantly conveys how the brother's near-misogynistic prurience about Betty's sexual past is the reflex of genuine (if libidinally charged) concern for her. But where you feel that LaBute knows this character from the inside, Betty proves to be a clutch of clichés about the ageing female beauty – as embarrassing as the schlock thunder-and-lightning that provides convenient power-cuts, without ever generating tension.

To 4 June (0844 412 4663)