Danny meets his evil opposite in Vlad Plasmius, a childhood rival of his ghost-hunting dad, Jack. Unfortunately, Vlad acquired ghostly powers 20 years ago, which means he's stronger and more experienced than Danny -- and hell-bent on taking everything away from Jack Fenton including his life.

Danny fears he's going to cause his parents' break-up when he knocks Jack's anniversary gift into the Ghost Zone. Desperate to retrieve it, he dives into a ghostly dimension where he runs afoul of Walker, the ghost warden of a ghost jail, and is thrown into prison with every ghost he's ever caught.

Noticing a change in little bro Danny since the accident in the lab, Jazz mistakes his ghost hunting for depression and signs him up for therapy with Penelope Spectra, not knowing that Spectra is a ghost who feeds off teen misery!

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.

Danny and Sam find their platonic friendship turned forcibly romantic through the musical powers of Ember, a hard-rocking girl ghost who feeds off the idol worship of teens. With her massive, free concert scheduled only a few days away a concert that will be broadcast worldwide and give her ultimate power Sam has to get the now completely and utterly love-addled Danny to focus on fighting ghosts. Even if it means breaking his heart.

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.

When Jazz falls for hunky boy ghost, Johnny 13, who can cast his shadow out and create bad luck for everyone who crosses him - especially the girls he's dating, Danny is forced to behave like an overprotective parent, much to Jazz's dismay.

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!

Maddie relishes the chance to bond with emotionally distant Danny at a weekend mother/son science seminar. However, the seminar is a ruse orchestrated by Vlad Masters - a.k.a. Vlad Plasmius, Danny's arch enemy! Vlad's plan is to convince Maddie and Danny to live with him while simultaneously destroying Jack with a massive ghost attack. When Vlad short-circuits Danny's powers, Danny gets to witness Maddie's impressive ghost fighting prowess. Meanwhile, a reluctant Jazz is pressed into ghost-fighting duty with Jack - and likes it, in spite of herself!