In Ealdor, Merlin's home village, Kanan leads his band of raiders into town, looking for Matthew, a farmer who has withheld food from the raiders to prevent the village residents from starving. Kanan, the raiders' leader, is furious that Matthew didn't give them the entire harvest. When Hunith, Merlin's mother, rushes at Kanan and angrily pleads with him not to let the children starve, he strikes her. A villager rushes toward them and Kanan swiftly kills him with a cross bow. In front of the terrified villagers, Kanan tells Matthew he wants the rest of the harvest in one week's time.
Hunith travels to Camelot, where Merlin's surprise at her visit quickly turns to anger upon noticing her bruised face. Arthur arranges an audience with King Uther, where she explains Ealdor's dire situation, adding the children won't last through winter. Uther asks why she hasn't gone to their king for help. Hunith says he cares nothing about the outlying villages. Uther sympathizes, but says that bringing an army from Camelot into Ealdor would be seen as an act of war. Despite her pleading, Uther says his hands are tied as it would undo a delicate truce that took years to achieve.
Later, Arthur sympathizes with Merlin, saying if it were up to him, he'd help. Merlin tells Arthur he must return home to take care of his mother. Understanding, Arthur thanks him for his service and jokes that Merlin's the worst servant he ever had. However, in seriousness, he says he'd do the same thing and wishes him luck. At Gwen's house, she provides Merlin with a sword, which he's not completely comfortable wielding, and armor. Morgana arrives and says they're accompanying him to aid in the fight for his village, citing that he's risked his neck to help them in the past.
Gaius sends Merlin off with camp supplies and provisions, and tells him to do whatever it takes to take care of himself. At camp, as Morgana and Gwen sleep, Hunith is worried that Morgana is with them and tells Merlin to be careful not to reveal his magical abilities. Merlin's confident that no one will find out, as they never do. Later that night, Merlin's awoken by the sound of an encroaching horse. He grabs the sword and goes to investigate, when he hears Arthur's voice behind him. He's so excited that he nearly decapitates Arthur with the sword when turning around.
The next day, Kanan and his raiders return, tossing the village in search of Matthew's hidden food reserve. Upon finding it, Kanan beats Matthew and is just about to deliver the fatal blow when Arthur, Merlin and crew ride in. Arthur makes quick work of a raider while Merlin gets pinned against a wall in a sword fight. He stealthily uses magic to scald his opponent's sword out of his hands, then finishes him off. Morgana fells a raider charging Arthur and asks if that reminds him of when she used to beat him. Annoyed, Arthur says that never happened. Clearly outmatched, Kanan calls his men back, telling the villagers they'll pay with their lives.
Merlin's old friend William, who saw Merlin enchant the sword, teases him about not wanting "his kind" here, then ribs him about "skivvying for some prince." Merlin says it's not like that, but Arthur defies that notion in William's eyes when he "orders" Merlin to gather the villagers. As Arthur tells the villagers to prepare for Kanan's return, William accuses Arthur of signing their death warrants so he can have the glory of battle. Arthur diplomatically defers to William, who thinks appeasing the raiders will save lives. Arthur says unless they fight, they'll keep returning. Despite William's protests, the entire village rallies behind Arthur.
Merlin tries to convince William that Arthur's intentions are genuine in defending their village, but William, whose father was killed fighting for their king, isn't convinced. When Merlin refers to Arthur as his friend, William challenges him, asking if Arthur knows about his magical abilities. When Merlin indicates he doesn't, William says Merlin's living a lie; that he's only Arthur's servant, otherwise he'd tell him everything. That night, Arthur asks Merlin why he left home. Merlin says he didn't fit into village life anymore and wanted to find somewhere that he did. Arthur jokes, asking if he's had any luck with that.
Next morning, Hunith tells Merlin she thinks Arthur truly likes him. Merlin says that's because he doesn't really know him and he'd be dead if Arthur knew his secret. Disagreeing, she says to give Arthur some credit. William finds Merlin collecting wood and asks why he has an axe when they both know he doesn't need it. William, the only villager who knows his secret, asks Merlin why he won't use sorcery to defeat the raiders. Merlin says Arthur will be a great king one day and needs his help to get there. If Arthur learned of his powers, he'd have to leave Camelot. William's chastises Merlin for putting Arthur before his friends and family.
Arthur trains the men of the village in basic combat. Upon seeing their basic skills, Morgana thinks there's no way they'll beat Kanan. Gwen says not if the women fight. Arthur sends Matthew to pick sentries to look out for Kanan. Later, when Morgana and Gwen pose the idea to let the women fight, Arthur says it's too dangerous. That night, Merlin overhears Gwen and Morgana saying they don't stand a chance, but Arthur can't see that because he's too stubborn. Gwen asks why Arthur came, and Morgana says because Arthur cares about Merlin, which is the same reason they came.
The next day, Matthew's dead body is sent back into town on his horse. A note is stuck on his back with an arrow, reading, "Enjoy this day. It will be your last. As Matthew's widow sobs over his body, William accuses Arthur of being responsible for his death. Arthur challenges him, asking what he's doing for his village. He tells the crowd they don't have a chance. As William packs to leave, Merlin says he's abandoning his friends and family. However, William, who knows Merlin can stop the massacre with magic, says he's the one abandoning them for refusing to use it.
Merlin explains to Arthur that William distrusts nobility because his father was killed while fighting for their king. Though Merlin says the townspeople won't be demoralized by William, a troublemaker they're used to ignoring, Arthur fears he's right. The men are farmers, not soldiers. Arthur reveals that he plans to tell the villagers to leave town, a wavering faith that Hunith overhears -- and -- her son convincing a prince to believe in them.
That night, when Arthur instructs the women and children to hide in the forest, Gwen says they have a right to fight. Upon seeing the resolve of the women villagers, Arthur agrees they should have a choice to fight for their home. And, that he'd be proud to fight alongside them. As William sits offside, Arthur gives a rousing speech on why they're fighting. Because they choose to fight, not because anyone ordered them to. And, that they fight for their homes and families, and Ealdor. Inspired, the villagers rise and chant "Ealdor!" William, the only one abstaining, leaves the rally.
Hunith fears that she's ruined everything for Merlin by going to Camelot. She tells Merlin that she knows he's planning to use magic. Merlin admits if it comes to a choice between saving people's lives and revealing who he is, then he'll indeed use magic. Hunith protests, saying Arthur can't learn of Merlin's gift, but Merlin says if Arthur can't accept him for who he is, then he's not the friend he hoped he was.
The morning of the raid, Arthur apologizes to Gwen for initially not wanting the women to fight. When he openly despairs about their chances, she tells Arthur she has faith in him, as does everyone else. Later, when Merlin tries to assist Arthur in suiting up in his armor, Arthur treats him as a peer, telling him to put on his own. Arthur shakes his hand and says it's been an honor. At that, Merlin's just about to tell him the truth about his magic when Morgana enters to inform them the raiders have crossed the river.
The raiders roar into town on horseback as the villagers hide in place and wait for Arthur's signal to move. Once they're close enough, the villagers activate a series of traps that herd the raiders inside an area encircled by a trench doused with flammable liquid. Morgana has trouble lighting the fire ring, so Merlin covertly uses magic to start it, spawning the fire to surround the raiders. At Arthur's signal, the men ambush the confused raiders. However, the more experienced villains soon turn the tides. Behind Merlin, a raider races toward him, his weapon poised to strike, but William, dressed in his father's armor, thwarts the attack.
Merlin is thrilled to see his friend there, who just saved his life. However, that elation soon turns to dread when they see the villagers, Gwen and Morgana struggling in a losing battle. "There's too many of them," William says. "Not for me there isn't," Merlin says, and uses magic to conjure a fierce whirlwind that sends the raiders flying into walls and off their horses. Once they flee, Merlin calls off the whirlwind. When the dust settles, an enraged Kanan, who remained behind, shouts Arthur's name, wanting to fight.
As the villagers watch, Arthur and Kanan go head to head, fighting a fierce duel, but the "trained from birth to kill" Arthur outmatches his opponent, running his sword through the vile raider, who collapses in disbelief. Arthur turns to William and Merlin, demanding to know who used magic to bring the wind up. As Merlin tries to stutter out an answer, Kanan lifts his crossbow to shoot Arthur in the back. William sees and shoves Arthur to safety, but his heroic action puts him in the line of fire. Kanan's arrow strikes him in the chest. Arthur's shocked that William saved his life.
Arthur, Merlin and the villagers carry the mortally wounded William to Merlin's house. To Merlin's shock, William, struggling to talk, tells Arthur that he conjured the whirlwind. Merlin tries to stop him, but William, knowing he's dying, says he did it when things got desperate. Arthur, though surprised to hear William's a sorcerer, is still thankful that he saved his life. They leave William and Arthur alone, where William tells Merlin that he wanted to give Merlin the chance to be the servant to a great king. As Merlin comforts him, William succumbs to his wound.
At William's cremation, Arthur shares his condolences with Merlin for losing such a close friend. He then tells Merlin that he realizes what he was trying to tell him before the battle was that William was a sorcerer. When Merlin confirms that, Arthur says that he should have warned him about something so dangerous.
Hunith tells her son that he has to go back to Camelot, as he belongs at Arthur's side. She's seen how much they need each other, and echoing the Great Dragon's words, says he and Arthur are like two sides of the same coin. She tells him how proud she is of him, and assures him that one day, when the time is right, the truth will be known. Until then, he must keep his talents hidden.