In early-19th-century England, a zombie plague has spread across the country. Miss Elizabeth Bennet, a young woman, lives with her parents and four sisters. Mr. Bennet drills his daughters in martial arts and weapons training, moulding them into capable zombie-fighters. Meanwhile, Mrs. Bennet endeavours to obtain for them wealthy and high-status husbands. Seeing an opportunity to achieve her goal, Mrs. Bennet sends her daughters to a local ball where a wealthy bachelor, Charles Bingley, is expected to make an appearance. At the ball, Mr. Bingley and the eldest Bennet daughter, Jane, make a connection in the midst of a chaotic zombie attack. During this time, Elizabeth meets Fitzwilliam Darcy, Mr. Bingley's closest friend and a noted zombie killer.
As time passes, Mr. Bingley and Jane become more acquainted. However, this companionship leaves the Bennet girls confused when Mr. Bingley and company suddenly abandon Netherfield Park. When the local militia arrives in town to exhume and destroy dead bodies, Elizabeth becomes friendly with one of the soldiers, George Wickham, who claims that Darcy cheated him of an inheritance.
Elizabeth's dislike for Darcy intensifies when she learns that he plotted to separate Bingley from her sister, Jane. Elizabeth vows to avenge the separation by killing Darcy, and she is afforded that opportunity when he appears unannounced at a cottage where she is visiting her newlywed friend Charlotte. Darcy surprises her by proposing marriage, and they break into a verbal and physical fight in which Darcy is wounded. He escapes and writes a long letter to Elizabeth explaining his actions: that he separated Jane and Bingley out of fear that Jane had contracted the "mysterious plague". With regard to the allegedly wronged soldier Wickham, Darcy explains that Wickham attempted to elope with Darcy's younger sister to take her considerable fortune – the "inheritance" that Wickham had claimed. Elizabeth realizes that she had judged Darcy too harshly and is humbled. Darcy realizes that his demeanour encourages people to believe the rumours about him and resolves to act more appropriately.
Elizabeth embarks on a trip around the country with her aunt and uncle, fighting zombies along the way. At Pemberley she encounters Darcy, who repels a horde of zombies. Darcy's changed attitude and manners impress Elizabeth and lead her to consider reconciling their relationship. However, that deliberation is crushed when her younger sister Lydia elopes with Wickham in London. The Bennet family fears the worst when they receive word that Wickham and Lydia have married, following an "accident" that has left Wickham as a quadriplegic. After visiting the Bennets, the couple moves to Ireland. Elizabeth eventually discovers that it was Darcy who engineered the union, thus saving the Bennet family from ruin.
Darcy and Bingley return to the countryside, and Bingley resumes courting Jane. Elizabeth hopes to renew her relationship with Darcy, but his aunt, the Lady Catherine, interferes and insists that her daughter Anne is a better match for her nephew. Lady Catherine challenges Elizabeth to a duel, committed to eliminating the competition, but Elizabeth defeats her. Elizabeth spares Catherine's life. Darcy is touched by this gesture and returns to Elizabeth. They marry and begin a long and happy future together, insofar as the ever-present threat of zombie apocalypse permits.