Robin Hood comes home after fighting in the Crusades to learn that the noble King Richard is in exile and that the despotic King John now rules England, with the help of the Sheriff of Rottingham. Robin Hood assembles a band of fellow patriots to do battle with King John and the Sheriff.

An assassin called Filthy Harry is hired by a shady figure and charged with killing the heroes. The men are framed twice for different robberies by King Kong's new girlfriend, nearly committed to a mental hospital by their devious boss, and forced to battle Filthy Harry's weaponry-laden robot while covered with time bombs.