
Skulker's on a looting spree, snatching up a number of seemingly unrelated items. Unfortunately, Danny's attempts to stop him are thwarted by the well-intentioned meddling of Danny's new sidekick: Jazz. However, Danny didn't ask for -- and doesn't want -- Jazz's help, and after a series of humiliating mishaps, Danny blows up at his sister. In response, Jazz runs away from home... to Vlad's castle in Wisconsin! But it's only a ruse. Jazz soon manages to break into Vlad's inner sanctum and discovers that he has been using Skulker to collect the items necessary to upgrade the Fenton's stolen Ecto-Skeleton. When Danny arrives at the castle, Vlad makes Jazz don the improved battle suit in a no-holds-barred fight against Danny Phantom!
Danny and Sam get into a fight, and when Sam utters the words, "I sometimes wish I'd never met you," she finds herself in a world in which she and Danny are strangers. Worse than that, since it was Sam who encouraged Danny to check out the Fenton Portal the night he got his ghost powers, Danny doesn't have any powers! Now, Sam must convince Danny that they share a friendship and a history, and lead him back to the Fenton Portal for a second "accident" so he can again become Danny Phantom.
After being bitten by tiny green ghost beetles, the kids of Casper High get a mysterious illness that gives them ghost powers and are quarantined at a spooky old hospital outside of town. When Danny sneaks into the hospital to investigate, he is captured by Penelope Spectra and her assistant, Bertrand. They are the ones who started this illness as part of their plan to build Penelope a young and beautiful new body. All she needs is Danny's half-human/half-ghost DNA to complete her ghostly plan. With Danny captured and Sam sick, it's up to Tucker to conquer his fear of hospitals and free Danny before Penelope gets what she's after.