On the island of terror, Doctor Claw’s giant servant Fong prepares to deliver a death-blow to the almost-stunned Captain Britain. The other British captives scream in horror, begging Claw to stop this. He is a beast, the actress Julie Vane accuses Claw. He takes the insult personal and points to the caged ‘beasts’ – that wait to devour them when their hero lies dead.
The snarls of the caged animals rouse Cap from his daze and suddenly he lunges at the huge man, wildly attacks and throws him down hard. And this time, Fong stays down.
Doctor Claw flicks a switch and his wheelchair soars skyward on jet lifters. With the help of his star scepter, Cap follows but, as he hears his foe, Claw presses another button and powerful blasts of air buffet the battling Brit, who finds himself helpless. His scepter cannot repel mere air.
Claw intends for his foe to learn an even more painful lesson. He jets towards his enemy, intending to use his claws to leave his foe’s visage as hideous as he is. Captain Britain uses that opening and lashes out with his scepter knocking Dr Claw and his jetcraft spinning though the air.
Cursing him, Claw tosses aside the blanket that covered his lower body, revealing the other loathsome effects the bio-chemical test had on his once human form. He reveals not the legs of a human being, but clawed twisted limbs, like some reptile’s.
With a bloodcurdling shriek, Dr. Claw closes in on the British superhero, attacking with all fours like a crazed jungle cat. Even his mind is no longer human, Cap realizes as he desperately defends himself. He is like some mad beast.
Meanwhile, in the arena, Fong revives, unnoticed by the Britons who are watching the aerial battle. He lunges towards them, intending to kill them.
High above, Captain Britain finally wrenches free from his enemy’s grip and jabs him fiercely with his sceptre. The mad doctor tumbles backward and plummets towards the ground before he fumbles his jetcraft back under control. At the press of another button, knives shoot out around the rim of each wheel – like deadly whirling scythes. He steers towards Cap again, vowing the hero will pay for what England did to him.
Instead of fleeing, Cap dives straight between the wheels. Claw rebounds from the terrific impact and Cap finally spies his companions on the ground.
Football star Bert Bullard leaps forward to protect the others, only to be hurled aside by Fong. Cap comes at him from behind. His diving blow sends the giant thudding to the ground. Fong reaches for a lever and General Mayhew, realizing that he intends to open the animal cages, shouts at Cap to stop him and hurls the trident towards him. A split-second later, the trident flies through the air and pins Fong’s arm before he can reach the lever.
Finally out of immediate danger, the Britons wonder how to escape and Cap states that Claw must have a transport somewhere. He follows Claw and finds he is heading for a certain mountain peak, an extinct volcano.
Cap flies inside to find the opening closes behind him – another trap. Claw intends to see him roasted alive and presses another switch. Lava drops in, but Cap has his force field to protect him. He flies at his foe and strikes him, causing Claw to fall against the high-voltage bus bars of the control panel, almost electrocuting him before Cap finds the off-switch. What he also finds is a jet plane and he quickly steers it towards his comrades.
While Claw fights to escape the scalding lava, the five prisoners leave, not giving too much about Claw’s chances, as his flying mutants are now out for his blood.