A tax collector is assassinated by a mysterious archer. The villagers suspect Robin Hood is the culprit, and the Sheriff of Nottingham uses this to turn the people against the outlaws, while Robin suspects the mysterious Night Watchman, who leaves food and medicines for the poor.
Several more assassinations turn public opinion against Robin and the outlaws, who are on the run from Guy of Gisbourne and his squads of hunting dogs. The Sheriff realises that Robin is not the culprit but blames him anyway, going as far as ordering De Fourtney to kill several more innocents to blame them on Robin.
Robin makes a deal with the Sheriff to catch the assassin, who is after the Sheriff, in exchange for calling off the dogs. The next day the Sheriff is attacked while visiting a village. Robin finds the Night Watchman and discovers that it's really Marian. The real assassin is revealed to be a castle guard who holds a grudge against the Sheriff and the tax collector. The Deputy (incidentally the Sherriff's look-a-like) is killed and the real Sheriff has Gisbourne murder the assassin and, separately, De Fourtnoy. Robin regains the trust of the villagers.