Every 2 years, a group of fire investigators meet for a conference. While attending the conference in 1987 in Fresno, California, 3 suspicious fires break out near the conference. They were in 3 different fabric stores nearby each other. The only clue being left behind is one latent pint. Two years later when the conference is held again in Monterey, California another group of fires break out. The firefighters at the conference begin to think that it's one of themselves. With fingerprinting in it's more advanced stage they were able to tie the arsons to one of the investigators. While searching through his things they find a manscript called DIARY OF A SERIAL ARSONIST which contained not only information on arson but instructions on murder. In the second story line an elderly woman from San Antonio, Texas lay in her room naked from the waist down with her throat slashed. In the next room was her 80 year old husband who had just suffered his 3rd stroke. But there was no evidence to charge him. With pressure from a Texas Ranger the case is re-looked at where in they find the LOST CLUE in solving the case.