Britt Reid, newspaper publisher, known only to his faithful valet Kato as The Green Hornet, archenemy of the racketeers is enjoying a vacation in Hawaii. During his absence, racketeers install one of their men on Reid’s paper as Managing Editor. Bordine, gunman, goes to Honolulu to prevent Reid’s return. But his plan fails, and he and Reid board the same boat returning to the United States. Learning Bordine is aboard, Reid, as The Green Hornet, enters Bordine’s cabin, and is forcing a confession from him when fire breaks out on the ship. Will our masked hero be able to put out the fire in time? Will he gain his confession from the evil Bordine?
Our hero Britt Reid, otherwise known as The Green Hornet, gets a leads that causes him to investigate the Kolten Munitions Plant. A visit to the plant proves unsatisfactory. As The Green Hornet, he calls on the Plant Superintendent at his home and learns a Crime Syndicate has defrauded the stockholders and just sold the plant to a foreign government for half a million dollars. The Hornet covers the Superintendent and his assistant, but they escape. The Hornet pursues, overtakes and is battling the Superintendent when they approach a bridge that is making way for a passing ship and their car flies off the bridge! Will the Green Hornet escape with his life? Will he lose the Superintendent in the confusion?
Britt Reid, publisher of "The Sentinel" learns that racketeers are victimizing Frances Grayson, heiress of the Aluminum Productions millions. Disguised as The Green Hornet, he calls at the Grayson home and finds Stella Merja, an actress impersonating Miss Grayson. Forced to explain, Stella confesses she has been hired to pose as Miss Grayson and sign over control of her company. The Hornet finds Miss Grayson a prisoner and is helping her escape when a tree, struck by lightning, wrecks their car. They take refuge in an unoccupied lodge, but are followed. Will our masked hero be able to fight off the villainous racketeers? Will Miss Grayson escape with her life and fortune?
Determined to get control of Aluminum Products Company, racketeers plan to cripple Home Electric, the company supplying them with power. Britt Reid, investigating complaints, visits the plant as The Green Hornet and finds two racketeers about to wreck the plant. The Hornet convinces the racketeers that he, too, wants to destroy the plant, and tricks them into believing he has lighted a fuse attached to powerful explosives. Then, under threat of the impending blast, attempts to force them to name their leader. Will The Green Hornet get their leaders’ name in time? Will he be able to stop the impending bomb?
Crogan, leader of the racketeers, sends Deluca with a crew running rifles over the boarder. Axford and Lowry become involved in an accident with the truck transporting the rifles. They identify Deluca, who is injured, and follow the car bringing him back to the city. Reid, as The Green Hornet, locates Deluca’s hiding place, and forces him to go with him to the warehouse where the rifles are stored. Crogan, fearing exposure, order his ace pilot to bomb the warehouse and with The Hornet and Deluca inside. Will the Hornet avoid the dropping bomb?
Our hero, Britt Reid, foe of the racketeers, sends two of his reporters to search the wreckage of a bombed warehouse. They find evidence linking the warehouse and the Grimbolt Steel Mills, where frequent suspicious accidents have been happening. Reid goes to the Grimbolt Mills to investigate, and barely escapes a serious accident. Convinced it was a deliberate attempt on his life, Reid, masked as The Green hornet, returns to the Grimbolt Plant, eludes the guards, surprises Weaver, a scientist secretly working on a highly dangerous anti-aircraft bomb. Will the Green Hornet obtain the evidence he needs to shut down the plant? Will he prevent the dangerous bomb from getting into the wrong hands?
Britt Reid, continuing his Grimbolt plant investigation, learns that a Dr. Beloe worked with Weaver on the anti-aircraft bomb responsible for so many accidents. As The Green Hornet, Reid calls on Dr. Bedloe, encounters and outwits the racketeers and, intercepting a telephone call, learns a test is being made of the bomb. Racing to the testing ground, The Hornet sees a plane taking off and, unaware it is to be a target for the bomb, boards a parked plane and speeds off in pursuit of the target. Is the Green Hornet flying to his death? Will the bomb strike him down?
Crogan, racketeers leader, desperately needing "quick" money, gets an idea from an article in the Sentinel that marks Frances Grayson as their victim. Britt Reid, worried over the article in his paper, sends Axford to guard Miss Grayson. Axford finds the racketeers in possession and forcing Miss Grayson to sign large checks payable to them. Masked as The Green hornet, Reid overcomes one of the racketeers and Miss Grayson is making her escape when another racketeer opens fire. Suddenly the lights go out. Will Miss Grayson be able to escape form the greedy men? Will The Green Hornet expose the evil racketeers?
Crogan, infuriated by a story in The Sentinel that exposes racketeers, order the "heat" turned on Reid’s paper. Hoodlums attacking a Sentinel delivery truck leave behind a coat in the pocket of which Reid finds an envelope addressed to a man named Smith. As The Green Hornet, Reid calls on Smith, who confesses that an unfinished building is to be blown up because the builder refused to join the racketeers. The Hornet races to the building and surprises one of the racketeers, but he denies guilt and refuses to confess. Will The Green Hornet get this vital confession? Will he be able to stop the impending explosion?
Britt Reid and his co-workers are rejoicing over the report that the oil well they helped John Fulton finance will prove a gusher. Fulton, bursting into Reid’s office, tells him that Cain, a lawyer who held his note for $10,000 changed the due date and attached his oil well. Disguised as The Green hornet, Reid forces Cain to confess he altered the note and gave it to Galt, now at the well. The Hornet goes to the well and a terrific battle ensues. Will Galt and his men overtake The Green Hornet? Will Fulton recover his losses stolen by the crooked lawyer?
Britt Reid and Axford witness the hijacking of a truckload of silk. They trail the hijackers, but are ambushed and Axford is taken prisoner. Reid telephones Kato to meet him with the Hornet outfit. Masked as The Green Hornet, Reid enters the isolated farmhouse where Axford is being held, overcomes the guard, ad forces him to confess that the racketeers have gone to Harbor Road to hijack another truck. The Hornet and Kato speed after the hijackers. Will our heroic pair be able to catch the racketeers before they get away with another hijacking? Will the hijackers prove too fast for The Green Hornet?
An avalanche of automobile thefts prompts Britt Reid to take Miss Case and Axford with him to investigate a suspected roadhouse. Racketeers at the roadhouse discover Reid’s presence and set a trap for him. Reid escapes, but case and Axford are taken prisoners to a warehouse. Masked as The Green Hornet, Reid forces the roadhouses proprietor into a limousine to show him the way to the warehouse. Crogan's men in the warehouse are busily loading explosives and motors from the stolen cars to trucks when the Hornet arrives. Will the Green Hornet be able to stop the evil racketeers? Will the stolen cars be salvaged and returned to their owners?
Our hero Britt Reid, suspects a conspiracy to defraud insurance companies when the third warehouse reported to contain military supplies is destroyed by fire. As The Green Hornet, Reid calls on Crawford, the warehouse owner, and forces him to confess that merchandise is removed from warehouses before they are set fire. Forcing Crawford to give him the location of a warehouse scheduled to be burned that night, The Hornet races to the warehouse, gains entrance and is making a hasty inspection when he is ambushed. Will our hero prevent the building from burning down? Will The Green Hornet be destroyed in the fire?
Britt Reid learns that Foranti, head of the Builders' Association, is stealing Association funds. As The Green Hornet, Reid calls on Foranti and forces him to hand over the stolen money. The Hornet then calls on Breedon, Foranti's undercover agent, but Foranti fires at Breedon and he falls. The hornet overcomes Foranti, but the police arrive and the hornet has to hide with Foranti in a car while Kato decoys the police into following him in the Hornet's car. Will The Green Hornet be able to escape the stern hand of the law? Will the stolen money be recovered to its rightful owners?
Will the Green Hornet finally bring the criminals to justice?