Siege of Monteriggioni

The Fall of Monteriggioni was a series of events leading up to an engagement between the Borgia, under the command of Cesare Borgia, and the Auditore which took place in January, 1500.

Return from the Vatican
"Steel yourself, Ezio. They will have many questions."

- Mario to Ezio, before returning to the villa.

After Ezio received the message of Those Who Came Before from the Vault under the Vatican, Ezio and Mario Auditore return to Monteriggioni after escaping the Papal forces, with the Apple of Eden with them.

At the countryside of Monteriggioni, Ezio and Mario conversed about what Ezio learned in the Vault, and as they rode to the city, mercenaries were testing out the cannons recently installed during Ezio's absence. Arriving at the city, Ezio and Mario was joyously greeted by the townspeople on their return. Arriving at the foot of the Villa Auditore, the two were greeted by Claudia, who told Ezio of Caterina Sforza's presence in Monteriggioni. Claudia then asked if what Ezio started was finally finished, to which Ezio replied that he will explain later in Mario's study, along with the others. As Claudia left, Mario told Ezio to prepare himself for many questions, before he went back to the Villa.

Before going to the villa, Ezio helped some of the townspeople, and while doing so, he learned of Claudia's birthday party from the townspeople. After helping the townspeople and some of Mario's mercenaries by delivering flowers to the Villa Auditore and testing out the new cannons himself, Ezio headed off to the Villa. Caterina Sforza stood waiting at the hall of the villa, who greeted Ezio with glee. Caterina sought out help from Ezio, asking for the assistance of his mercenaries to defend against the Papal army. Ezio told Caterina that they will discuss things after the meeting at Mario's study, to which she agress, as she followed Ezio to the meeting place.

Ezio arrived at the study, where Claudia, his mother, Mario, and Niccolò Machiavelli were waiting. Ezio explained what he saw in the Vault and his confrontation with the Spaniard, Rodrigo Borgia. In the Vault, Ezio met the goddess Minerva, who told Ezio of a disaster that will occur in the distant future, and also mentioned the existence of temples that can aid humanity. After her message, called out to a phantom named Desmond, much to Ezio's confusion. After this, the goddess disappeared.

The others were astounded by Ezio's journey. Claudia asked if the goddess appeared human. Ezio told her that she did, though her words proved otherwise. Mario asked who Desmond was, and where were the Temples that Minerva mentioned. Ezio did not know the answer. Machiavelli asked Ezio how it ended with Rodrigo, if he begged for mercy or offered power. Ezio told him that none of these happened, for he did not kill Borgia. Enraged, Machiavelli told Ezio that it was a mistake to let him live. Ezio tried to explain why he spared Borgia, that they should forget the past and focus more on the future. Machiavelli disagreed with the Assassin, and abruptly left for Rome.

As Machiavelli left, Mario tried to comfort Ezio with his decision, stating that he made the right move. After this, Ezio leaves the study and returned to his room. There, he undressed and bathed. With him was Caterina, who "comforted" him while bathing. After the bath, Ezio and Caterina continued their "activities" in bed, which lasted until dawn.

Siege
"We've had too much bloodshed. I think a cleansing is in order. So consider this as an invitation from my family...to yours!"

- Cesare Borgia, moments before killing Mario.

As they finish, Caterina asked Ezio if he wants to "go again". Ezio replied that she need not to ask. As they were about to begin, cannon fire can be heard from the outside. When Caterina wondered aloud what it was, Ezio assumed it was just the mercenaries training with the new cannons. This was proven wrong, as a cannon ball tore through the windows of Ezio's room, destroying the armor of his ancestor. Surprised, Ezio got out of bed and dressed himself for combat. Taking up a common sword and his hidden blade, while dressed in common clothes, Ezio headed out of the villa through the wall blown open by cannon fire. Caterina leaves the room through the stairs and tells Ezio that she will assist the civilians. After this, the two part ways.

What greeted Ezio was the site of Monteriggioni, under cannon fire, with buildings and structures burning and falling apart. As his eyes wandered, Ezio sees a cannon ball headed his way, which he barely dodged. Ezio falls off the roof of the Villa, but was able to recover quickly. He was then helped up by his uncle, who told him that the Borgia has come to attack them. Ezio wondered why they were not able to see them coming, to which Mario replied that they must've taken a different route to the east. As the Villa fell apart, Mario instructed Ezio to climb the walls of the city and help the mercenaries as the villagers flee. Mario told Ezio that he will lead a frontal assault against the Borgia.

Ezio asked his uncle if he had the apple, to which he replied that he is keeping it safe. After this, the two bid each other safety and farewell, before Ezio tells Mario to be careful, with Mario reassuring him that he will be. Ezio, with haste, dropped off the villa's courtyard and jumps onto a horse, where he rode across the city as it fell apart. Arriving at the side of the city walls, a building nearby falls, which causes Ezio's horse to trip and fall. Ezio dismounts just in time, and proceeds to climb up the tower, after small nuisances. Ezio made his way to the mounted cannons, which he used to defend the city from cannon fire. As Ezio and the mercenaries defend the city, the townspeople flee to safety. After all the townspeople made their way out, as Ezio manned the cannon, the siege towers arrived at the side of the city walls. One of the mercenary took Ezio's place, as the assassin prepared to defend the other side of the wall.

Ezio made his way to the other side, and disposed off all the soldiers. As he did, he sees from afar, his uncle Mario arriving at the city gates, barely alive. Who followed was Cesare Borgia, along with some of his generals and his sister Lucrezia. Cesare called Ezio out, stating that he knew of him and the Assassins, and also the apple. Ezio rushed to Mario, as Cesare takes a gun fashioned by the assassin's friend, and points it to Mario's head. Claiming that a cleansing is in order, Cesare shoots Mario with the gun, serving as the invitation of the Borgia to the Auditore. Subsequently, Ezio was shot across the shoulder by one of the arquebusiers at the city walls, which causes Ezio to fall into unconsciousness.

Escaping the city
Waking up, Ezio is greeted by the site of two mercenaries, dragging him across the ground. Ezio abruptly told them to let go, stating that he can stand on his own. As he did, the Borgia's soldiers arrive to finish off what they began. Knowing he cannot handle the guards alone, Ezio called for the mercenaries to back him up, to which they did. After a brief fight, Ezio and the mercenaries made their way to the villa, to meet up with Claudia.

As he made his way through the city rubble, Ezio arrives at the villa, and sees Claudia and a group of mercenaries being assaulted by more soldiers. Ezio and his group of mercenaries assisted them, and successfully fended them off. After this, the group made their way to the Sanctuary, taking out everyone that stood in their way. Eventually, Ezio made his way to the Sanctuary, after being greeted by one of the thieves of Monteriggioni. The thief told Ezio that they thought he was dead, before asking where the passage led to. Before Ezio closed the passage to the sanctuary, the thief left to aid the other factions assisting Ezio. After this, Ezio locked the secret door to the hidden passage, before meeting up with the others.

Ezio met up with Claudia, his mother, and the other civilians. There, he led the escape through a long passage constructed behind his ancestor's statue, that leads to the outside of the northern walls. After a long journey, navigating through the complex structure and dealing with the guards that managed to catch up with the group, Ezio and the other civilians managed to escape the city.

Aftermath
While asking for a horse, Ezio instructed Claudia to take their mother back to Florence. Claudia asked where he was headed, to which he replied that he was going to Rome. As the civilians leave the area, and as Maria bid her son farewell, Ezio rides off to Rome. In the midst of his journey however, Ezio passed out.

After a while, Ezio woke up, covered in bandages. He was greeted by the sight of a kindly woman, who nursed him back to health. There, she told him that a man took him there and left new equipment for him to use. After this, the woman instructs Ezio to meet up with Niccolò Machiavelli at the Mausoleo di Augusto.

The liberation of Rome has begun.

Source

 * Assassin's Creed: Brotherhood