In early 19th-century England, a zombie plague has spread across the country. Mrs. Bennet endeavours to obtain for her daughters wealthy and high-status husbands. Seeing an opportunity to achieve her goal, Mrs. Bennet sends her daughters to a local ball. 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. When zombies attack, the Bennet sisters use their martial arts skills to keep the human attendees safe.
Soon after, Jane is invited to visit Netherfield. Mrs. Bennet insists she travel on horseback rather than in a carriage. While traveling, Jane is attacked by zombies and injured. Elizabeth receives a letter informing the family that Jane will stay at Netherfield to recuperate, and insists on joining her sister. During their stay, Elizabeth interacts with Mr. Bingley, his family, and Mr. Darcy often. Once Jane is fully recovered, Mr. Bingley is persuaded by Mrs. Bennet to throw a ball.
Jane and Elizabeth return home. The odious heir to Longbourn, Mr. Bennet's cousin Mr. Collins, arrives with the intention of marrying one of the Bennet daughters and settles his attentions on Elizabeth. When the local militia arrives in town to exhume and destroy dead bodies, the Bennet sisters also meet the charming George Wickham, whom Mr. Darcy and Mr. Bingley seem to avoid. Wickham explains to Elizabeth that he grew up with Mr. Darcy, but they had a falling out after Wickham was denied the living he had been promised by Mr. Darcy's late father, justifying Elizabeth's negative opinion of Mr. Darcy. She looks forward to meeting Wickham again at the Netherfield ball, but later learns he was not invited. Mr. Darcy asks Elizabeth to dance. The ball is interrupted by a zombie attack, which is thwarted by Mr. Darcy.
The next day, Mr. Collins asks Elizabeth to marry him. She refuses, angering her mother. Mr. Collins instead proposes to Charlotte Lucas, Elizabeth's best friend and a spinster, who accepts. She has been secretly infected with the 'mysterious plague' and hopes Mr. Collins will be too oblivious to notice her slowly becoming a zombie. Jane receives a letter from Caroline Bingley, informing her that Mr. Bingley and his party are en route to London with no plans to return soon. The letter also convinces Jane that Mr. Bingley wants to marry Darcy's younger sister.
Elizabeth's dislike for Darcy intensifies when she learns that he purposefully 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", and that Wickham had lied about not receiving his inheritance. Elizabeth realizes that she has judged Darcy too harshly whilst Darcy realizes that his demeanour encourages people to believe the rumours about him and both resolve to correct their personal short-comings.
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. The Bennets spend time with Darcy, his sister, and Mr. Bingley, who still has feelings for Jane. The visit ends abruptly when Elizabeth learns Lydia has run away with Wickham and she returns home to support her family.
A letter is delivered to Longbourn, stating that Lydia and Wickham are now married, Wickham's numerous debts have been settled, and he is now crippled. Elizabeth eventually discovers that it was Darcy who engineered the union and paid Wickham's debts as well as Lydia's dowry, thus saving the Bennet family from scandal and financial 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.
