A rash of arsons throughout the city stumps the Green Hornet and Kato, the District Attorney, and the Fire Department. Each one has occurred at precisely midnight, but no one can determine the precise location or who is behind it all.
Following the latest fire, Britt Reid, D.A. Scanlon, Mike Axford, and others attend a conference on the problem held by the Fire Department Commissioner. Mike suggests that the Commissioner hires former firefighter Bill Wade, who lost his eye and was forced to leave the department. Fearing that Wade might further injure himself, the Commissioner refuses.
Later, someone dressed in a fire suit sneaks past a guard at a factory and sets it ablaze. The guard calls the fire department and goes to investigate, but the arsonist knocks him out. Seconds later, the Green Hornet arrives and Kato knocks the fleeing arsonist to the ground. However, as the Green Hornet saves the guard, the arsonist knocks Kato out and flees to his house, where it is revealed that he is actually Bill Wade.
Mike, who was waiting to tell Wade that Britt Reid might hire him as an investigator on the arson case, attempts to call the police, but Wade stops him. The next day, Britt goes to Wade's for information on the missing Mike and tells him he is hired. Later, Britt tells Wade about some replacement medical supplies being stored in a Sentinel warehouse, disguised as newspaper supplies.
Wade begins preparing for one last arson, this time bringing Mike along to take the blame for it and all the others. Moments after he arrives at the warehouse, the Green Hornet arrives. He confronts Wade, who begins throwing homemade grenades at the Hornet and Kato, which set the warehouse on fire. Green Hornet gets into a fistfight with Wade, and Wade is knocked into the flames, where the Hornet can't get to him.
The next day, Mike asks Britt to downplay the arsonist story. He feels that his late friend deserves a better epitaph. Britt agrees and he and Ms. Case both feel bad for Mike about the whole situation.