Mabouse invites the colonel to confirm that the warhead is now active. Once he does, the colonel warns the scientist that he won't get away with his plan, and Mabouse has Varna stun him unconscious. Meanwhile, the Green Hornet and Kato are in the Black Beauty and homing in on the Hornet tracker in Shugo's pocket. As they close in, Kato switches their car to silent mode to avoid detection by Mabouse's sensors.
Mabouse's men transfer the warhead to their truck and drive away. They get word that their plane has arrived in the area, but Mabouse decides to lay low a little longer to avoid detection. He scans for police broadcasts and picks up the signal from the Hornet tracker. The scientist assumes that Shugo is working with the Green Hornet and has betrayed them.
The heroes home in on the signal and proceed on foot. They find Mabouse talking with his men, and Kato throws a Hornet dart. It shatters against a mirror, and they realize that they've been tricked. Mabouse and his men step out of the woods and capture them at gunpoint, and Mabouse expresses his admiration for the Green Hornet. The scientist assumes that the heroes are there to take the warhead if he fails, but Mabouse assures them that he won't fail. He ties up the two heroes along with Shugo and puts the three of them in the Black Beauty. Mabouse then sets explosives beneath the car and rigs the Hornet's Sting to trigger them. He then hooks up a motion sensor to the Hornet's Sting. If the Green Hornet or Kato fail to set it off, the police will trigger it off when they arrive.
Once Mabouse leaves, the Green Hornet comes up with a plan. He tries to reach the switch that triggers the rear rockets, hoping the recoil will push them clear of the explosives. The hero manages to wiggle into position, but Shugo panics and leaps out. The rockets go off, pushing the Black Beauty clear, and the explosives detonate, killing Shugo.
An Air Force helicopter trails Mabouse in his truck, but keeps its distance for fear of provoking the scientist into triggering the warhead. Mabouse tries to raise the escape plane on the radio but gets no response.
The Green Hornet and Kato realize that Mabouse plans to escape by air and head for an abandoned airstrip. Scanlon meets with the Air Force and they reach the same conclusion. They order fighters into the air to cut off the escape plane and prevent it from landing.
When Mabouse learns that his escape route has been cut off, he orders his men to pull the truck over so he can set off the warhead and get his revenge. His lieutenant, Martin, insists that they didn't sign up for mass slaughter and begs Mabouse to reconsider. Mabouse draws a gun on Martin and forces him to stay behind with the bomb while he escapes with Varna and the others.
The Green Hornet and Kato spot the fighters and realize that Mabouse will come up with another plan. They find Martin and the bomb, and the henchman tells them that Mabouse has a remote that he'll use to trigger the bomb once his truck is at a safe distance. The heroes drive after Mabouse and the Green Hornet makes a dramatic leap to the truck. Kato forces the truck to the side of the road and leaps out to take on the thugs on the outside, while the Green Hornet takes out the crooks inside. Mabouse loses the remote in the confusion, and tries desperately to find it. Varna throws an electrical blast at the Green Hornet, who reflects it back at her with a piece of mirrored glass. The hero then subdues Mabouse just as he finds the remote. The Green Hornet takes the remote with him and escapes with Kato, and then disarms the nuclear warhead.
Later, Britt and Kato invite Casey and Scanlon over. Scanlon explains that Varna used a portable electrical device to generate her lightning bolts, and the "saucer" was an iridescent weather balloon. Mabouse faked the crash with gasoline and junk metal. Britt leaves for his postponed date and a night at the opera, turning down Scanlon's offer of the lightning projector to liven things up.