Robin and the gang capture a messenger from Isabella to Prince John with a letter: apparently, Isabella wishes to send 300 men to Prince John to assist him. Members of the gang inform Robin in a hurry that 100 men each have been taken away from Clun and Nettlestone villages, and they figure out that Isabella wishes to get the remaining 100 from Locksley.
We jump right into action. A stern-looking black man with an almost demonic voice, Blamire, is commanding the operation, taking prisoners to be conscripted. Robin and the gang interrupt him and free the prisoners, killing many guards; the rest retreat.
Archer enters Nottingham to seek out Isabella, but she arrests him and orders him to be thrown into the dungeon, mostly because she doesn't want her mother's memory to be stained by the fact that she had given birth to Archer out of wedlock (she also resents Archer's dishonorable nature). However, while being escorted, Archer takes advantage of the terrible quality of padlocks in Nottingham to break free of his bindings and escape.
Robin leads the people of Locksley to the forest. He and Tuck argue; Tuck wants to form a militia out of them, while Robin is averse to the idea.
Isabella, meanwhile, plots to separate Robin Hood from his friends. She wants to break Kate away by bringing in her mother, threatening her, and ordering her to plant one half of her medallion onto Robin, to make Kate believe he still loves Isabella. Kate's mother has a convenient opportunity to do this next time the gang visits Locksley, planting the piece of the medallion onto Robin while pretending to hug him, and telling Kate how Robin still loves Isabella. The medallion accidentally drops to the ground while they go back to the forest, but Guy picks it up. Robin doesn't know why it is there, and initially suspects Guy of foul play, but they can't figure out who would carry it and why, so Robin puts it on his bed.
Archer wants to buy some information that he can sell to Isabella in exchange for getting enough money to leave England. He finds a shady man in the Trip Inn who tells him about the secret tunnel in exchange for a bag of gold. Meanwhile, Guy tells the gang about the tunnel as well and proposes that instead of trying to storm the castle with peasants, they go through there and capture the Sheriff. Kate doesn't trust Guy, but Robin forcefully tells her that he trusts Guy now. Kate is downcast, and that's when she discovers Robin has Isabella's half of a medallion on his bed. Feeling betrayed, she leaves.
Isabella tells Blamire to announce that Allan A Dale is exonerated for services to the Sheriff, to make the gang think he betrayed them again. As he leaves, Archer sneaks in through the tunnel and confronts Isabella alone. He offers to build her a trap in the tunnel that can kill Hood in exchange for a lot of money. Isabella eventually agrees.
The gang hears how Allan has been given immunity from prosecution. A temperamental Little John rushes back to camp and threatens to strangle Allan. Robin tells him to let go, but everyone believes Allan did betray them, so they tie him up and agree to sort this out after they're done in the castle. After Tuck tries to convince the peasants to fight, and Robin argues with him a little, Robin, Guy and Much leave for the tunnel, while Tuck and Little John head towards the castle gates.
Kate returns to her mother and tells her about Robin's affair. The mother can't live with her guilty conscience and tells her how Isabella forced her to trick her. She tries to half-heartedly convince her to stay, but Kate rushes off to help the others.
Inside the tunnel, Robin, Guy and Much fall for Archer's trap. They are trapped inside a small room, with something white pouring inside, threatening to suffocate them eventually.
Allan frees himself from his restraints and runs away, complaining to himself about how they didn't trust him. However, an unexpectedly large number of soldiers begin to pursue him. He subdues a few and starts to run to warn Robin.
Little John and Tuck turn up at the castle gates, which are closed. Their task is to stop a cart of supplies from being delivered to Prince John, although it is not clear how they will do it by themselves. Suddenly, the peasants turn up, armed with pitchforks and torches (both of them are surprised by this, showing they expected to be fighting alone).
Tuck, realizing that they would be massacred if they fought, decides instead to appeal to the humanity of the Sheriff's soldiers, organizing a literal sit-in strike by telling the people to sit down in the path of the carriage and try to stop the soldiers through pacifist methods.
Allan is running to warn Robin, but is shot by several archers. He is approached by a mysterious individual in a cloak - Allan, shocked, exclaims "You!" before being killed off-screen.
Blamire and his soldiers begin to move out with the carriage; Archer tags along not far behind to see what's going on. They are surprised to discover the peasants sitting in front of them, Tuck and Little John at the front. Blamire orders his men to draw their swords; they do so, albeit reluctantly. After a brief scene where we see Robin and his two companions still struggling with the trap, slowly giving up, Blamire goes forward and moves to strike down Tuck, but he can't bring himself to strike the man down.
Isabella comes out to see what's going on, and ordering Blamire to stand back, shoots Tuck in the shoulder with a crossbow. Still, Tuck doesn't budge, and prevents Little John from standing up and doing anything. Isabella orders the men to cut the peasants down, but Kate arrives just at that moment, telling a guard to "start with her then", taunting him about how he wouldn't be willing to cut down an innocent girl. Egged on by Isabella, the guard raises his sword and moves to strike Kate down.
Archer, seeing the scene and having a change of heart, throws some sort of throwing knife at the guard and kills him. He draws his sword and suddenly, everyone springs into action, including the peasants, and they begin to fight the guards. The wrath of the people proves too much for the guards to handle, who are overwhelmed; Isabella quickly retreats into the castle. Once the fighting settles down, Archer tells the others that Robin and his friends are dying in his trap, and Kate and Archer hurry to free them. Kate and Robin do a little kissing before they all hurry back to the castle.
A panicked Isabella begs Blamire to help him against the peasant mob, but the man claims he can't help; he tells the confused Isabella to deliver Gisborne to the secret tunnel if she wants to live, before leaving somewhere. Kate then arrives, and a short "catfight" ensues between the two women, partly over Robin, before everyone else turns up and subdues Isabella.
Robin announces to a jubilant crowd that Nottingham has been liberated, but an alarmed Much calls the gang to the gates, where someone has deposited Allan's corpse, wrapped in a cloth. As they close his eyes, Guy is the first to notice hundreds of Prince John's soldiers approaching. In the last scene, we see Blamire riding out and joining the surprise individual, Sheriff Vaisey - it turns out Blamire had just been Vaisey's plant all along, preparing the castle for his glorious return. The Sheriff, pleased, anticipates the upcoming fight. The episode ends on a cliffhanger. (It is not made clear how exactly Vaisey got all these men; the simplest explanation is that he simply sweettalked Prince John and got back in his favor - not a hard task at all with the vain Prince.)