Sharona's actress sister, Gail, is suspected of murdering Hal Duncan, a fellow actor who dies onstage after Gail stabs him with what she insists is a retractable knife. When Sharona's mother (who thinks that Sharona is Monk's partner, not his assistant) arrives for a visit and Sharona tells her the bad news, Monk and Sharona promise to ""do whatever it takes"" to discover what really h