The Battle of Prentiss Island was a battle with hunter Dean Winchester and vampire Benny Lafitte against the vampirates led by The Old Man so that Benny could get revenge for his own murder and the presumed murder of Andrea Kormos.
At some point in the past, a man named Benny Lafitte was transformed into a vampire by the vampire known only as The Old Man. Benny joined The Old Man's organization of vampirates and raided private yachts for people for the vampirates to feed on. However, during one such raid, Benny fell in love with Greek heiress Andrea Kormos and left his life as a vampirate behind. Benny and Andrea moved to Clayton, Louisiana where they started a life together and Benny fed off of donated blood bought off of the black market. However, The Old Man was not content to let Benny go and tracked Benny down. The vampirates killed Benny and the last thing he saw was The Old Man ripping out Andrea's throat, leading Benny to believe that The Old Man had killed her as well. However, unknown to Benny, The Old Man changed his mind and changed Andrea into a vampire herself. Andrea became a vampirate and eventually rose to become The Old Man's second in command.
Following his murder, Benny's soul was sent to Purgatory where all monsters go when they die. About fifty years later, Benny met hunter Dean Winchester who had become trapped in Purgatory after killing Leviathan leader Dick Roman. Benny offered Dean a deal where he would help Dean find the missing Seraphim Castiel and get out of Purgatory if Dean would bring Benny back with him. Dean took the deal and eventually returned to Earth where he resurrected Benny.
After his resurrection, Benny began seeking out the vampirates, both because he knew they would come after him once they learned of his return and to get his revenge for Andrea's perceived murder. Benny was able to track Quentin down to Eagle Harbor, Washington and killed him and two other vampirates, but was badly injured. Benny's injuries caused him to call upon Dean for help with getting the blood he needed to heal and Dean offered Benny his help against the vampirates once he learned of Benny's goal. Using a cable bill Benny found amongst Quentin's things, Dean and Benny are able to track the vampirates to nearby Prentiss Island.
Armed with their Purgatory Blades, Dean and Benny enter the house on Prentiss Island where the vampirates have their nest. While Benny pauses to examine The Old Man's harpsicord, Dean urges him to keep going and moves into another room. On a table next to the harpsicord, Benny is horrified to find a picture of Andrea Kormos whom he had believed murdered along with him. At that moment, Andrea herself comes down the stairs and she and Benny are both shocked to see each other. As they stare at each other, Sorento and two other vampires enter the room and attack Benny, subduing him. Safely in another room, Dean witnesses the attack unnoticed, but is unable to help Benny.
Benny is handcuffed to a chair with Sorento holding his own weapon to his throat and taunting him. Andrea confirms that The Old Man turned her into a vampire when asked by Benny. Andrea then orders Sorento to go and tell The Old Man that its true about Benny being back. Benny is surprised to realize that Andrea can give orders to Sorento and she explains that she now answers to The Old Man alone and he trusts her judgement over that of Sorento's. Andrea slaps Benny when he accuses her of sleeping with The Old Man before ordering the other two vampirates away to make sure The Old Man has everything he needs.
Andrea then kisses Benny and expresses relief at his return. Andrea explains that The Old Man apparently changed his mind for some reason about killing her and turned Andrea instead. She'd stayed with the vampirates due to her need for blood. Telling Benny that neither she nor any of the others can kill The Old Man but he can, Andrea slips him a knife and the keys to his handcuffs. Sorento then returns with the message that The Old Man wants Benny brought before him.
While Benny is held captive, Dean makes his way through the house, ignoring a call from Sam and ducking into a room to avoid a vampirate. Dean then calls Sam back and explains to his enraged brother that he's taking down a vampire's nest with "a friend" and that it has gone wrong. Dean texts Sam the location of the nest so that he can come and help. Noticing a vampirate coming, Dean leaves his phone in a dish on speakerphone so that Sam's angry rant draws the attention of the vampirate. While the vampirate is distracted by the phone, Dean comes up behind him and decapitates the monster when he turns around. However, this results in Dean's phone getting smashed.
As Dean attempts to drag away the dead vampire's body, he is found by another vampire, but quickly kills him. While moving the bodies, Dean is found by two more vampirates who follow him around a corner. However, Dean quickly and easily kills them. He then continues his search through the house for more vampires.
Benny is brought before The Old Man by Sorento with his hands handcuffed behind his back. The Old Man expresses surprise at Benny's resurrection and asks for an explanation. Benny simply tells The Old Man that he found a way back from something that's "right next door" to Hell. Benny refuses to explain what he means and instead suggests that he'll just have to show The Old Man what he means. The Old Man expresses regret for killing Benny and tells him that he turned Andrea to salvage something from his "wayward son" and to have something to remember Benny by.
The Old Man admits that everything that has happened leaves him feeling "so tired", but he couldn't let Benny go before because he isn't willing to let things go. Benny reminds The Old Man that he has lived for centuries and all he has to show for it are "a beat-up old harpsicord and a nest of hyenas." When The Old Man reminds Benny that he has Andrea, Benny reveals that The Old Man doesn't and shows him the handcuffs he removed with Andrea's key as proof. Enraged, Sorento attacks Benny, but Benny's fighting skills are superior from his time in Purgatory and he easily disarms and overpowers Sorento before killing Sorento with his own weapon.
Benny then turns on The Old Man and challenges him to fight. However, The Old Man refuses, telling Benny that he was right about The Old Man who has seen so much and is tired of the universe which he sees as a "pit of despair." The Old Man taunts Benny about how simplistic his view of the world is, being evil, compared to Benny who has always had to think things out. As The Old Man taunts him, Benny attacks, throwing The Old Man into a cabinet and demanding that he fight. The Old Man refuses, telling Benny that this is the final thing The Old Man can take from him by ending his own "story" the way he chooses. Drawing Andrea's knife, Benny tells The Old Man that he can finally show The Old Man something new: "a whole, new, world." Benny then uses Andrea's knife to kill The Old Man, finally getting his long-desired revenge.
Benny returns to the main room where Andrea is waiting for him, puts the bloody knife down on the harpsicord and declares that "The Old Man is dead." However, Andrea refuses to leave with Benny and he realizes that she isn't planning on coming with him and never was. Andrea reveals that she wants to take over the vampirate operation for herself and Benny now, unaware that Dean has killed the rest of the vampires. Benny tells Andrea he had wanted to "leave a burning crater behind" and put her memory to rest by destroying the vampirate operation. While Andrea insists that she's not a memory and is right there, a horrified Benny understands that the woman he loves died a long time ago, killed by monsters like him and what Andrea has become. Benny admits that he doesn't think that he's better than Andrea but that "we're all damned." Enraged, Andrea moves to attack Benny, but Dean comes up and stabs her through the stomach from behind. Dean then decapitates Andrea, killing her and shares a sorrowful look with Benny.
After the battle, Benny exhibits signs of depression over the loss of Andrea and wonders about Dean's willingness to resurrect him. Returning to the mainland, Benny meets Sam who realizes that Benny is a vampire, causing problems between the Winchesters for a while.
Following the death of Andrea and getting his revenge, Benny returns to his hometown to take care of his great-granddaughter Elizabeth from a distance to have something to keep him going. After being forced out of his hometown by the actions of Desmond and Martin Creaser, Benny's depression grows worse when Dean cuts off contact shortly thereafter. As a result, when Dean asks Benny to return to Purgatory months later to rescue Sam and Bobby Singer, Benny chooses to go with no intention of returning as he feels he no longer belongs on Earth.
- This battle is the only time Dean Winchester and Benny Lafitte are shown using their Purgatory Blades in combat together outside of Purgatory.
- While Dean had previously used the blade against demons in We Need To Talk About Kevin, this is the last time he uses it in combat in the present on the series. The blade is thereafter seen hanging in Dean's room in the Men of Letters bunker.