San Francisco Playhouse continues its season with “The 39 Steps,” a fast-paced farce that riffs on the Alfred Hitchcock thriller of the same name. Following a mysterious murder, all-action hero Richard Hannay launches on a high-speed chase from a London music hall to Scotland’s highlands, where he must dodge devious spies, woo beautiful bombshells, and attempt to reveal secrets of The 39 Steps, an international spy ring. With inventive stagecraft and masterful performances, four nimble actors play more than 100 characters in this riotous spoof that is equal parts slapstick comedy and film noir thriller. San Francisco Playhouse Producing Director and Co-Founder Susi Damilano, who recently directed the Playhouse’s hit production of the whodunit “Clue,” returns to the scene of the crime(s) with this rollicking comedy.