Juan Pablo Diaz went on a mission recently, but not quite the type of mission he expected. He wound up living the parable of the Good Samaritan - from the perspective of the beaten man.

Like many of his friends in Guatemala City who were members of The Church of Jesus Christ of Latter-day Saints, in 1996 the young Diaz packed his white shirts and ties and postman shoes and scriptures and set off to preach the word. In his case, the destination was Panama.But then something happened - something unexpected. In the flush of youth, missionaries - in fact, most of us - think these unpleasant surprises always happen to someone else. But this time, Diaz himself was the "someone else."

In October of last year, halfway into his mission, Diaz, 20, started getting very tired. He had a hard time working. When walking or riding his bike with his companion his heart beat so hard he could literally hear it.

Consultations with a Panama City cardiologist resulted in a diagnosis of a heart murmur, for which Diaz was given pills and sent back to the streets. But the hoped-for remedy didn't work.

"It just kept getting worse and worse," he said.

By December, Diaz had a continual fever and was sick indeed. He wound up in the hospital, where additional tests revealed that he had bacterial endocarditis, an infection inside the heart.

The condition is very serious, and fatal without treatment. Diaz's heart was so greatly enlarged it was three times its normal size.

After serving only 14 months of his mission, Elder Diaz was sent home to Guatemala for treatment. The infection had completely destroyed the aortic valve, which controls blood flow from the heart into the aorta, the main artery of the body.

"It was something I never expected," he said.

But the truncated mission was the least of Diaz's troubles - he was in danger of his life. Medical resources in Guatemala were limited for the complex (and expensive) aortic valve replacement procedure, and Diaz's father, Guillermo, a shoe leather wholesaler, was terribly worried about his son.

Enter those whom the Wizard of Oz simply but accurately labeled "good-deed doers."

Salt Lake City's LDS Hospital and thoracic surgeon Donald Doty agreed to donate their services to help Diaz, if he could find a way to get to Utah. The LDS Church agreed to fly him and his family up. On March 16, Doty replaced Diaz's damaged aortic valve with one of his pulmonary valves, then used a donor valve to replace the pulmonary valve. The former missionary was released a week later.

"The surgery went very well," Doty said. "Looking at him today you wouldn't recognize him as the same person that I saw when he first came here. He was a very sick young man. But his prognosis is good, and I expect he will lead a very healthy and active lifestyle," including the basketball and dancing Diaz had loved so much.

So, 17 months after waving goodbye to his family to become a missionary, Diaz is where he never dreamed he would be - Utah, attending LDS General Conference, living with relatives in West Valley City.

On Monday he returns to Guatemala. He is convinced he has another mission there, a different and vaguely defined mission, to be sure, but one the Lord has ordained.

"In the beginning (when the illness started) I was disappointed, but I learned a lot of patience," he said. "Now I think I have a lot of things to do in my life."