It is among the most controversial of phenomena and the hardest to explain. It is said to consume its victims from the inside out, turning them to cinders while leaving their surroundings relatively untouched. Sometimes the fire is so localised that the victim's torso and head are destroyed while the legs and hands actually remain intact. One victim was engulfed in a fire so intense that it decimated her in less than 20 minutes. Believers in the phenomenon go head-to-head with sceptics and fire investigators. Interviews include emergency personnel who answered emergency calls and saw the remains of victims. We also hear from fire experts who investigated deaths that have been allegedly caused by Spontaneous Human Combustion, relatives of the victims as well as actual witnesses to the deaths.