George Wickham is introduced as a member of the local militia who has a shared history with Mr. Darcy. Mr. Wickham's charming demeanor and his story of being badly treated by Darcy attracts the sympathy of Elizabeth Bennet. It is revealed through the course of the story that George Wickham's true nature: he is a liar, a charmer, a gambler, a manipulator and a zombie
Wickham was the son of the late Mr Darcy's steward and grew up alongside Mr. Darcy. Darcy's father treated Wickham like a second son supporting him and paying for his education and training in Japan alongside Darcy.
Before the Film
As the pair grew older, Wickham was to be left a large inheritance by Darcy's father and upon this discovery, the late Mr Darcy was mysteriously infected by the zombie plague leaving Darcy no choice but to behead him. Wickham denied the living in the Church he was offered and instead asked for £3000 whereupon he asked for more and more money until Darcy eventually refused. After that, an angered Wickham severed all ties to the Darcy family.
A year before the events of the film, Wickham attempted to elope with Georgiana Darcy, Darcy's fifteen year old sister, for her £30,000 inheritance and to revenge himself on Darcy. However Darcy discovered the plan and sent Wickham away managing to convince his sister of Wickham's "ulterior motives".
Wickham was then infected with the zombie plague whilst in the militia at an unknown time. He blamed Darcy for his infection using his hatred of him to calm his hunger for human brains.
In the Movie
Wickham first appears alongside his friend Captain Denny as they have been positioned in meryton to deal with the zombie resurgence. Lydia openly flirts with him until Elizabeth steps in and chasticises her. Wickham escorts the Bennets and Parson Collins to their aunt's house whereupon the group run into Mr. Bingley and Mr. Darcy the latter of whom he was history with. The pair exchange looks and become extremely agitated in the other's prescence.
When the two gentlemen leave, Elizabeth, who has noticed the exchange, asks what history the men have together. Wickham lies telling her that Darcy cheated him out of an inheritance because he felt that he was "unworthy" and gave it to another man.
At the Netherfield Ball, Wickham does appear (something that does not occur in the book) and briefly talks with Elizabeth before Parson Collins takes her to dance. He mentions that Darcy must go not himself but later vanishes from the party before it is revealed that a group of zombie orphans have been let in to the kitchens.
The next day he runs into Elizabeth- who has just gone into the woods to escape her mother - and takes her to St Lazarus Church. The Church feeds zombies of the In-Between pigs brains instead of human ones so that they keep a piece of their former humanity. He tells Elizabeth that he wants to bring an alliance between the Living and the Undead but due to the Crown being drained, he has no financial support to make the venture work.
Due to this, Elizabeth brings Wickham with her to see Lady Catherine de Bourgh one of the richest women in Britain and also Darcy's aunt, who as it transpires, is also staying at Rosings Park. Both Lady Catherine and Parson Collins laugh at the notion of "zombie aristocrats" and once Darcy learns Wickham is after money, he sends him away.
Later that night he approaches Elizabeth and tells her that Darcy "brags" about having split up Jane Bennet and Mr. Bingley. He also asks Elizabeth to elope with him but she refuses and tells him he "has crossed a line". Wickham makes remarks hinting to his true zombie nature before leaving.
Before Elizabeth returns home, he elopes with Lydia Bennet and takes her to St Lazarus to keep her as a hostage. He also organises strategic zombie attacks on the heavily fortified London increasing the zombie numbers and destroying the city.
When Darcy himself comes to rescue Lydia, Wickham refuses the offer of money to leave and release Lydia stating that "money is no use to [him] now". He tries to shoot Darcy but the bullet ricochets off metal grating and attracts the now fully converted zombies of St Lazarus. Darcy escapes with Lydia as Wickham is swallowed up by the hoarde of zombies.
Wickham then reppears moments later having somehow survived the attack to fight with Darcy whilst the zombies swarm towards Hingham Bridge. The duel lasts all night with Darcy finally gaining the upper hand and impaling him in the early hours of the morning. However Wickham does not die and begins choking Darcy who rips open his shirt in the ensuing struggle revealing a zombie bite mark.
Wickham reveals that he had been a zombie the entire time continuing to choke Darcy and declares that the Four Horsemen of the Apocalypse have risen to crown him King of the Undead. Before he can kill Darcy however, Elizabeth rides past and slices his sword arm off and knocks him down with her horse. When Hingham Bridge is destroyed, it is assumed that Wickham was either killed or became trapped in the In-Between.
In a Post Credits scene, Jane and Bingley, and Darcy and Elizabeth, are leaving their wedding reception when they see a huge hoarde of zombies charging towards them led by Wickham now with a wooden mace as substitute for his severed arm.