Inspector Kurt Wallander sat in his office at the police station in Ystad and yawned. It was such a huge yawn that one of the muscles under his chin locked. The pain was excruciating. Wallander punched at the underside of his jaw with his right hand to free the muscle. Just as he was doing so, Martinsson, one of the younger officers, walked in. He paused in the doorway, puzzled. Wallander continued to massage his jaw until the pain subsided. Martinsson turned to leave.

"Come on in," Wallander said. "Haven't you ever yawned so wide that your jaw muscles locked?"

Martinsson shook his head.

"No," he said. "I must admit I wondered what you were doing."

"Now you know," Wallander said. "What do you want?"

Martinsson made a face and sat down. He had a notebook in his hand.

"We received a strange phone call a few minutes ago," he said. "I thought I'd better check it with you."

"We get strange phone calls every day," Wallander said, wondering why he was being consulted.

"I don't know what to think," Martinsson said. "Some man called from a phone box. He claimed that a rubber life-raft containing two dead bodies would be washed up near here. He hung up without giving his name, or saying who'd been killed or why."

Wallander looked at him in surprise. "Is that all?" he asked. "Who took the call?" "I did," Martinsson said. "He said exactly what I've just told you. Somehow or other, he sounded convincing." "Convincing?"