A wealthy businessman is apparently killed in an earthquake, but Monk is sure that he was murdered by his wife. The trauma of the earthquake temporarily worsens Monk's condition by causing him to talk gibberish, but he recovers soon enough to communicate his suspicions to the beleaguered captain, who has his hands full with fires, false alarms, and looters. Meanwhile Sharona is forbidden to enter her apartment because of earthquake damage, so she and Benjy are forced to spend the next few days with Sharona's snippy and competitive sister, Gail. They are quickly joined by Monk and Sharona's latest Mr. Wrong, whom the viewer knows is really the lover of the dead man's wife. Complications arise when the conspirators decide that Sharona knows too much and Monk, who has mentally reconstructed the crime, again loses the power to speak English after going through an aftershock. The captain, who has just begun to investigate a second murder in Sharona's neighborhood, receives an unintelligible call from Monk. Fortunately Gail is there to tell him the one thing he needs to know--Sharona is in trouble.