In 1501, a city in Italy has been taken by a coup d'état while its rightful ruler, Arnolfini (Fernando Hilbeck), is away. Arnolfini promises some mercenaries 24 hours of looting if they succeed in retaking the city, and they do so well, raping and killing those who stand in their way. But in their revelry, Arnolfini decides that he wants them gone. Hawkwood (Jack Thompson), the commander of the troops, is caring for a young nun he mistakenly attacked and injured during the siege. Arnolfini promises to get medical attention for her and Hawkwood leads Arnolfini's cavalry, betraying his former lieutenant, Martin (Rutger Hauer). The cavalry ejects the mercenaries from the city without their loot. Soon after, Martin's son is stillborn. Burying the infant unearths a wooden statue of Saint Martin of Tours-a saint with a sword. The mercenaries' cardinal views this as a sign from God to follow Martin as their new leader.Arnolfini's son, Steven (Tom Burlinson), is betrothed to Agnes (Jennifer Jason Leigh). They meet for the first time and eat from a mandrake to magically fall in love, then the entourage is attacked and robbed by Martin's band. Arnolfini is seriously injured; Kathleen, Agnes's lady-in-waiting, is stabbed in the chest and dies; and Agnes is hauled away, concealed among her valuable dowry. Martin discovers Agnes later that evening as they strip the caravan of valuables. The men desire to gang rape her but Martin decides to take her himself. He rapes Agnes while she at first taunts him and then begins to flirt with him, hoping to gain Martin's protection.The mercenaries come upon a castle where, unknown to them, the inhabitants are infected with the plague. They capture the castle easily with the help of Agnes. She induces Martin to fall in love with her and works on the other mercenaries to accept her. She appears to have given up on her former life. Meanwhile, Steven is determined to rescue her and turns to Hawkwood. Hawkwood only wants to live a quiet life, married to the former nun he had injured. Steven, becoming as ruthless as his father, seizes the nun to force Hawkwood to help his pursuit of Martin. They locate Martin and the mercenaries. They do not have sufficient force to take the castle and lay siege to it. In the castle, Martin asks Agnes where her true loyalty lies; she is noncommittal, hinting that the winner takes all. Outside, the plague spreads among Steven's forces and infects Hawkwood.Steven builds a siege tower to storm the castle, and Martin destroys it with something Steven had tried earlier: gunpowder. Steven's soldiers are killed as Steven scales the tower's ladders, and he falls into the castle grounds. The mercenaries capture Steven and shackle him in the courtyard. Agnes pretends to join in the abuse of the captive Steven and even makes love to Martin in his presence. Using a new medical technique Steven had learned (cutting the buboes on the infected body), Hawkwood cures his plague. He cannot continue the siege alone but, before leaving for additional troops, he catapults pieces of an infected dog into the castle. One chunk lands near the chained Steven, who flings it into the castle's water well. Agnes sees this and Steven tells her that she can decide whether to tell the mercenaries.The mercenaries wish to leave the castle, fearing the plague, but Martin persuades them to stay. At the next meal, Agnes watches as they drink infected water. As Martin begins to drink, she slaps the cup from his hand. Many mercenaries soon show signs of the plague sickness and hurl Martin into the well. As she did after Steven's capture, Agnes pretends to join in the abuse of Martin. Hawkwood and Arnolfini have recovered from their wounds and return with an army. Inside the castle, Steven needs Martin's key to escape from the shackles, and Martin needs Steven to get out of the well. The two cooperate, but upon seeing the besieging army, Martin flees to the belfry. Steven frees himself and, as the battle rages, races to find Agnes. During the fighting, the belfry catches fire. Before long, all the mercenaries but Martin, Polly, Anna, and Little John are dead.Martin confronts Agnes. She claims that she loves him, but he prepares to murder her rather than allow her to return to Steven. As Martin is strangling Agnes, Steven attacks. Martin, a cunning and hardened mercenary, overpowers Steven. He almost drowns him, but Agnes strikes Martin on the head, and she and Steven flee the blazing castle and reunite with Hawkwood. As Agnes and Steven embrace, Agnes sees Martin over Steven's shoulder, escaping from the castle, a sack of loot on his shoulder. She says nothing