American brothers, Max and Chris, arrive in a small European town to spend the summer with their eccentric uncle Gustav. Max becomes sure that their uncle is a vampire and goes to see the rich local businessman Alexander Lucard for help.
Gustav's old friends Peter and Anna Dyson arrive for a visit. Meanwhile, Lucard finds out that Max has taken the Cross of the Magyars which prevents vampires from entering Gustav's home from the house to be blessed.
While Sophie and Chris skirt around the relationship issue between them and finally end up on a date together, Max meets a clumsy, but brilliant, scientist who has made it his life's work to invent items for battling the undead.
When a man named Paul Yeager loses his wife to Lucard's second-in-command, Klaus, he attempts to enlist Gustav to help him kill the vampire, but Gustav is strangely unwilling to help. Meanwhile, the children go on a treasure hunt.
Gustav appears on "Cleo Talk" to debunk a professional psychic, Lana Zorro, but she astounds him when she is able to read his mind. Meanwhile, the kids find Dracula's tomb.
The rich and famous Contessa de Suarez has chosen Sophie to be her guide while she's in town. When Sophie learns that the Contessa is staying with Lucard, she grabs Uncle Gustav's vampire hunting equipment and rushes to the castle.
Helsing invites lounge performer Mycroft Tickler home for dinner, only to discover that he is brother to Magnus St John Smythe, the bungling inventor of the anti-vampire laser gun, and that Lucard has invited him to dine at the castle.