When a vat of "white hot metal" spills onto foundry worker Pat Dempsey, something amazing happens.  "Through an inexplainable chemical reaction of the skin texture," whenever he is exposed to heat thereafter, he turns blue, begins to flame and can burn his way "through the thickest barriers." 
 
Quitting his job, he decides to become a private detective.  Despite his name, Man O'Metal is a man of flesh and blood, able to be knocked out or killed when he's not aflame.  In his active state, however, any weapon or projectile that comes near him will melt.