If you go to Anthony Shaffer's "Whodunnit" at the Megaw, don't give up at intermission. The first half, in which a swarthy blackmailer issues demands to a long line of stereotypical guests at an English country manor, is such a hackneyed set-up for a murder that the management attempts to goose the suspense by conducting a whodunit contest at intermission.
Yet the second act brings big changes. I can't begin to disclose what happens, but we do see why the first act was so pedestrian, and we go home with minds tickled, if not provoked. The play is just a lark, but at least--at last--the lark begins to sing.
Perhaps a more polished cast than director Sydney May Morrison's would manage to make even that first act interesting. Nevertheless, Miguel Marcott as the slimy extortionist, Steve Peterson as a young bounder and Jan Cobler as an ingenue do their first-act roles stylishly, and some of the other actors join them in the second act. The set looks cramped.
Performances at 16701 Saticoy St., Northridge, are Wednesdays through Saturdays at 8:30 p.m., Sundays at 5 p.m. through Dec. 14, and Jan. 8 through Feb. 1 (818-881-8166).