"Who?"

"Our client," Mason said.

"She could be lying?" Della asked.

"Of course she could be lying," Mason said. "And she's just the type who would lie. She's a young woman who has sharpened her wits against the seamy side of life. She knows her way around and she's doubtless learned that everyone must look out for himself. That's the code of the society in which she's been living."

Della Street said, "Then she would have stolen the gun from The Big Barn, gone aboard the yacht, only instead of not finding anybody aboard, she had a session with Nadine Ellis and killed her. Then she came here and handed you the gun, telling you her story about having found it in her baggage."

"That's right," Mason said.

"And at that very time Mrs. Ellis must have been lying dead on the yacht."

"In that case," Mason asked, "how did the yacht get out there beyond Catalina Island?"

Della Street gave his question thoughtful consideration. "The yacht was safely moored in the harbor after you switched guns?"

Mason grinned. "It must have been," he said, "and that fact is going to give Hamilton Burger, the district attorney, and Lieutenant Arthur Tragg of Homicide, a terrific jolt. That fact, Della, puts our client in the clear and puts us in the clear."

"Just how will the D.A.'s office get jolted?" Della Street asked.

"Finding a gun in Ellen Robb's possession, thinking that it's the murder weapon, getting everything all built up, turning the fatal bullets over to the ballistic department and then finding that they didn't come from that gun at all."

"In that event, what gun did they come from?" Della Street asked.

Mason stroked the angle of his jaw with the tips of his fingers. "I wish I knew the answer to that," he said. "It doesn't seem possible that the bullets could have come from the gun that we returned to The Big Barn… but if they did… if they did, we're in one hell of a predicament, Della."

"What would we have to do?"

"I'm darned if I know," Mason said. "If I keep quiet I'm perhaps compounding a felony, perhaps making myself an accessory after the fact-to use a legal expression-in a murder case."

"And if you go to the police and tell them the story?"

"If I go to the police and tell them the story," Mason said, "they won't believe me. They'll think I am simply trying to work some elaborate scheme to trap the police and throw the prosecution off the track. And in any event I'd still be in a jam, this time for betraying the interests of a client."

"Are you honor bound to keep all the facts in connection with her case confidential?"

"Probably not," Mason said. "Strictly speaking, a privileged communication is rather limited. A lawyer is technically only entitled to protect the confidences of his client within a very limited field. The confidences are those that are given to the attorney in order to enable him to represent the interests of his client.

"That's the narrow, technical rule. Practically, by both usage and custom, the rule has been expanded. I know as far as I'm concerned, I'd rather have my hand cut off than betray the interests of a client. If I'm representing a client, I want the representation to be honest, loyal and efficient. I make it a point to believe everything my client tells me and to act accordingly in order to protect the best interests of that client."

"Yet you recognize there's a possibility the client may lie?"

"I recognize the possibility the client may lie," Mason said.

"Well," Della Street said, "as I see it, there's nothing to be done until the police get a report from the ballistics department on those bullets."

"That's right," Mason said. "After they find out that the bullets that killed Mrs. Ellis didn't come from that gun, then the question is, did they come from the gun we took from Ellen Robb? If they didn't, we're in the clear. If they did, then we're right slap-bang behind the eight ball."

"We can find out?" Della Street asked.

"We can find out," Mason said, "because fortunately I had Paul Drake get a ballistics expert to fire test bullets from the gun. We have those test bullets. Paul Drake can get photographs of the fatal bullets, and we can compare the striations. That's not the best way of making a comparison, but it will do under the circumstances. We can reach a pretty fair opinion. In other words, if the test bullets don't match the fatal bullets, we can tell. If they do, we can't be absolutely certain. But if we get enough lines of striation in the photograph, we'll know that there's a very good possibility the fatal bullets were fired from that gun."

"And then?" Della Street asked.

"Then we'll cross that bridge," Mason said. "We should be hearing from Paul any-"

Drake's code knock sounded on the door. Mason nodded to Della Street, who opened the door and let Paul Drake in.

Mason, standing in the middle of the office floor where he had paused mid-stride when Drake knocked on the door, nodded to the detective, said, "What's new, Paul?"

"I hate to bring bad news," Drake said, "but if the ballistics check shows that Nadine Ellis was killed by a bullet from the gun that the police took from Ellen Robb's motel room, she doesn't stand the faintest whisper of a chance."

"And if the bullets don't check?" Mason asked.

"They've probably got a case against her," Drake said, "but it won't be dead open-and-shut."

"I don't see what evidence they have," Mason said, frowning.

"Well, naturally they're not telling," Drake said. "From what I can pick up in the way of scuttle butt around Headquarters, they seem to feel they have an airtight case-and, of course, once the ballistics experts show Nadine Ellis was killed by a bullet from that gun the police took from Ellen's motel, they have a case that neither you nor any other lawyer can win. That ballistics evidence will make it a copper-riveted cinch."

"All right, Paul," Mason said. "I've got some confidential information for you. The gun won't check. Now, start working on the case from that angle and see what your investigation shows up."

"You mean the bullets weren't fired from that gun?"

"They weren't fired from that gun."

"How sure are you, Perry?"

"Positive."

"That's going to make a difference," Drake said. "But, look, Perry, you can't be positive. You never know when a client is lying to you and when she's telling the truth. Particularly a girl like Ellen Robb. She can be convincing as a liar. She's a past master at pulling the wool over your eyes."

Mason said, "Nobody's pulling the wool over my eyes, Paul. The bullets won't check."

"Well, that's something," Drake said. "There's one thing certain. If they don't check, that will hit the district attorney an awful wallop right between the eyes."

"He's going to be hit a wallop, then."

Drake was thoughtful. "There's only one way you could be certain, Perry."

"How's that, Paul?"

"That gun you gave me to take to Maurice Halstead, Perry."

"What about it?" the lawyer asked.

Drake was thoughtfully silent.

"Well?" Mason prompted.

"Look, Perry," the detective said, "if you pulled one of those gun-switching acts of yours, and if that gun I gave Halstead should prove to be the murder weapon… well, I'm bailing out, that's all. I can't go that far."

"No one's asked you to, Paul."

"I'd have to tell what I know."

"When?"

"As soon as I knew it made any difference in the case."

"We'll let it stand that way," Mason said.

"I'm not going to sleep tonight, Perry," Drake said.

"Take a pill."

"That won't help. Good Lord, Perry, do you know what you're doing?"

"It's not what I'm doing that worries me," Mason said. "It's what I have done."

"So what do I do now, Perry?"