Bud attempts to sell the teeth to Troy, played by Peter Stormare, at a pawnshop but receives low offers that do not solve his financial issues. Although the union pays better, Bud is unlicensed, forcing him to rely on Troy and the black market, which offers less money. For the two vampires' fangs, he only earns $2800. He urgently needs cash because his ex-wife Jocelyn, portrayed by Meagan Good, plans to relocate to Florida with their daughter Paige, due to high private school fees amounting to $5000. To afford the school bills and braces costing $4800 for Paige, Bud has just seven days to find the funds. This situation drives him to return to the vampire hunting union, even though he had previously been expelled for his reckless and aggressive hunting methods that violated union rules.
With the assistance of his friend John Elliot (Snoop Dogg), who is well-regarded in the union, and its leader Ralph Seeger (Eric Lange), Bud gets a second chance with the union, but under strict rules. In his earlier tenure, Bud acted recklessly, putting civilians at risk and launching attacks on vampires near innocent people. He also jeopardized the life of a fellow union member. Now, he is restricted to working only day shifts, which pay less, and must be supervised by a union representative named Seth (Dave Franco). Seth's job is to watch for any violations by Bud and report them. Although Seth prefers not to work in the field, Seeger promises him a promotion if he can find a violation committed by Bud. Bud trades his fangs at the Union but has to pay a joining fee of $5000, along with a 15% commission and a 50% deposit until he completes his paperwork.
Meanwhile, a vampire named Audrey (Karla Souza) discovers the bodies of the vampires killed by Bud and grieves for the deceased. She has found a method to survive in sunlight by staying in the shade. While searching for Bud, she encounters the pawnshop owner, whom she tortures, interrogates, and ultimately kills. Audrey reveals that humans once worshipped vampires as deities before they turned against them and expresses her intentions to restore that ancient "god worship" system. Seth is completely inexperienced in this area. He understands the theory but can't handle emergencies. Juvie vamps are newly turned vampires from existing ones. They have not yet learned to consume human blood and rely on animal blood for survival. There are five types of vampires: Southern, Eastern, Spider, Uber, and Juvie. They are categorized by age, and they fear sunlight above all else. Although they cannot reproduce, they can transform humans into vampires. Bud chooses to target Juvies, even though their pay is lower, because he is short on time.
At the same time, Bud is killing vampires with Seth to gather the money he needs. Seth must stay close to Bud, which leads to him being attacked by vampires. After his first encounter, Seth is so frightened that he wets himself and throws up. Bud gives him a special powder to cleanse himself because a dead vampire releases a scent that allows other vampires to track down their killer. Bud lives next to Heather, who is his friend and works as a nurse. Even though he breaks multiple rules, Seth chooses not to report Bud after discovering his intention to support his family financially. Bud, along with Mike and Diran, locates and eliminates a large vampire nest due to the variety of species cohabiting. Audrey tracks down Bud, threatening his family and revealing that the ancient vampire is actually her daughter.
In a hurry to save his ex-wife from vampires, Bud can't reach her in time, resulting in his family being taken hostage while Seth turns into a vampire. Hungry, Seth attacks Bud, but Bud manages to decapitate him. Surprisingly, Seth survives and decides to assist Bud. Now, Bud must rescue his family and thwart Audrey's scheme. In a conversation with Heather, she expresses her dislike for working with Audrey but claims she has no choice. She also reveals that the vampire Bud killed earlier was Audrey's daughter. Seth and Heather (Natasha Liu Bordizzo) assist Bud in attacking Audrey’s stronghold, with John joining them. Inside Audrey's hideout, they discover a factory producing a sunscreen that enables vampires to thrive in sunlight, which could lead to their domination of Silicon Valley. During the battle, John gets bitten and ultimately sacrifices himself so Bud can proceed to rescue his family. Though Bud struggles against Audrey, he cleverly tricks her in the fight. He uses his last bullet on her, which causes her to charge at him, but she inadvertently decapitates herself because Bud had placed a silver wire at head level. This allows him to save his family.