In the movie Van Helsing, set in the late 19th century, Gabriel Van Helsing is a legendary monster hunter working for a secret society called the Knights of the Holy Order. He is sent to Transylvania by the Vatican to help the Valerious family vanquish Count Dracula, their greatest enemy.
The Valerious family has been cursed for generations by a werewolf ancestor who failed to kill Dracula and his three brides, resulting in the loss of his family's honor and the inability of his descendants to enter heaven. The only way to lift the curse is to kill Dracula.
When Van Helsing arrives in Transylvania, he meets Anna Valerious, the last of her family, and her brother Velkan, who has been turned into a werewolf and is being held captive by Dracula. Anna explains that Dracula has made a deal with Dr. Frankenstein to bring his monster back to life, hoping to use him to create an army of unstoppable creatures that will help him take over the world.
Van Helsing and Anna set out to stop Dracula, but they face many obstacles along the way. They have to fight off werewolves, vampires, and other monsters, as well as deal with their own personal demons. Van Helsing struggles to remember his past and redeem himself for a sin he cannot remember committing, while Anna is torn between her duty to her family and her growing feelings for Van Helsing.
As the story unfolds, Van Helsing and Anna discover that Dracula's plan is even more sinister than they thought. He wants to use the power of the werewolf to create a new race of hybrids that will rule the world, and he needs Anna's blood to achieve his goal.
In the climactic battle, Van Helsing and Anna team up to take down Dracula and his minions, with the help of Frankenstein's monster and Velkan, who sacrifices himself to save his sister. In the end, the curse is lifted, and Van Helsing returns to his life as a monster hunter, while Anna and Frankenstein's monster start a new life together.