When ghosts wreck a popular co-ed's school social life, she dedicates herself to hunting them, which forces Danny to deal with a threat just a few lockers down the hall. Worse yet, Tucker has a crush on the girl.

Living dual lives as a high school freshman and a superhero is a balancing act for Danny that just got even tougher, with both Lancer and his parents pressuring him to ace a test. At the same time Technus ghost master of technology has escaped into Danny's online game and threatens to flee into the Internet and take over every computer in the world!

In an attempt to beat Dash in a haunted house decorating contest, Danny 'borrows' the enchanted sword of the Spirit of Halloween, the Fright Knight! When the evil, ghostly knight comes to retrieve his magic saber, he decides to stick around long enough to turn the real world into his own stormy realm of terror. Danny Phantom has other ideas, and banishes the Fright Knight to the Ghost Zone.

Amity Park is thrown into chaos by the town's first mass invasion of ghosts. It's all part of a plan by the Ghost Zone's top Sheriff, Walker, to capture Danny Phantom. As Danny first battles, then befriends, a hulking ghost named Wulf, Walker and his deputies ""overshadow"" most of the people in Danny's inner circle. While eluding attacks from his ghost-fighting parents, Danny defeats Walker and restores calm in the city - but earns the title of ""Public Ghost Enemy #1"" in the process!