Bruce Lee has just died, but the BSI is swinging into action to salvage the situation. Aided by the brilliant Professor Lucas, cells from the martial arts master's body are removed and grown into three adult Bruce Lee clones. After undergoing training to bring their skills up to the level of their 'father', the three are sent out to battle crime, with one sent to take on a gold smuggler, and the other two teaming up to shut down an evil mad scientist.

Tang Lung arrives in Rome to help his cousins in the restaurant business. They are being pressured to sell their property to the syndicate, who will stop at nothing to get what they want. When Tang arrives he poses a new threat to the syndicate, and they are unable to defeat him. The syndicate boss hires the best Japanese and European martial artists to fight Tang, but he easily finishes them off. The American martial artist Colt is hired and has a showdown with Tang in Rome's famous Colosseum.