(intro narration) Night. Cat is driving his sportscar, and dropping off the lovely Dr. Kathryn DeVrees at the Country Hospital where she works. They have a long kiss; Cat is in love with her, this time it's serious. After Cat drives away, a gunshot rings out; a man is shot. Kathryn kneels over him and gives him first aid, but he dies in her arms. Then she looks up and sees the face of the killer: Juan Sonorrito; since she could now identify him, he must kill her, too. But as a doctor and some nurses rush out, the killer disappears for now. He will be back.

Cat is in Kathryn's bedroom, the penthouse on the 30th floor. Cat kisses her goodnight; he will guard her apartment all night. In the living room, McAllister talks to Cat; McAllister says Kathryn can testify, the other witness is dead. Joseph Reinhoff hired the killer, and Kathryn's testimony will put him away; Reinhoff will be finished, as will half the criminals in the city. Cat wants to be the lone guard in her apartme