Having surmised from the ring he took from the Sheriff's sister that she has connections to the Sheriff, since the ring carries his insignia, Robin secretly observes a series of mysterious black- cloaked figures entering the castle, which is otherwise totally locked down. Allan, tricking inn customers using the egg and cup trick, is captured by Guy. Robin meanwhile goes to visit Marian, who has just come back from a mission as the Night-Watchman, and unsuccessfully tries to convince her to join him. He then fails to stop Guy taking her and Edward back to the castle as hostages and burning down Knighton Hall. He is prepared to shoot Gisbourne but a shaken Marian shakes her head. At the castle, Guy of Gisborne and Marian talk briefly of their unsuccessful wedding, with Gisbourne reminding her she can't embarrass a man of his power at the altar without consequences.
Robin meets a woman called Rose, actually the Sheriff's sister in disguise, tied to a stake in Nottingham market place, taking a punishment for her children, and promises to help her. He discusses this with his band, then returns to see the Sheriff about to cut off the children's hands, although it has been revealed to the audience that the children are actors in the Sheriff's service. In attempting to save them, Robin is trapped and the deception is revealed. Robin is hung above a pit of snakes and sees the black-cloaked figures he had seen entering the castle revealed as "the black knights" and hears them and the sheriff discuss Operation Sha-Mat (i.e., Check Mate, i.e., kill the king). This is a plan to kill King Richard wherever and whenever he lands back on English soil, and take over the country with a mercenary army paid for by punitive taxation. As this is going on, Gisborne is hitting Robin repeatedly with his bow. The Sheriff then has Robin lowered inch by inch towards certain death in the pit, but Marian, as the Night Watchman, causes a distraction and leaves the castle. But while the fighting is going on the Sheriff shouts at the Night Watchman that Robin is dead, which devastates Marian.
Left alone, Robin manages to tip over a pile of pikes across the pit and reach safety, but is stopped by the sheriff's sister. In a struggle, the sister ends up in the pit and Robin and the sheriff, who has returned, try to save her. They get her out, but she has been fatally bitten and dies in his arms, but not before saving her brother from being killed by Robin by telling Robin how Prince John has threatened a scorched earth policy against the whole of Nottinghamshire should Robin kill the sheriff. The Sheriff vows revenge on Robin, who has meanwhile escaped from the chamber, and then - with Much, Will and John's help - from an ambush by Guy. Marian walks through Nottingham still crying over Robin's apparent death. He appears around the corner and she is overjoyed, though Robin again fails to convince Marian to join him - her father Edward is still the sheriff's hostage, and she returns to him. Robin returns to his band, as does Allan, who has been released by Guy on the condition he will be his spy in Robin's camp.