When Paulina witnesses Danny's ghost transformation, he fears the exposure. Imagine his surprise when Paulina swears to keep his secret - then becomes his girlfriend! Life is great for Danny, until he finds out that Paulina has actually been overshadowed by Johnny 13's girlfriend, Kitty, in her plot to make Johnny jealous. Danny reluctantly plays along to protect his own identity, but, when Kitty's welcome wears thin, Danny pleads with Johnny 13 to take her back. When Kitty abandons Paulina's body and goes back to her true love, Paulina resumes her indifference towards Danny Fenton - although she's now madly in love with Danny Phantom!

Danny and Valerie Gray are forced to become ""parents"" to a sack of flour for a one-week school assignment. At the same time Skulker, ghost hunter extraordinaire, decides to pit Valerie and Danny Phantom against each other in a contest - with the winner earning the privilege of becoming his prey. When Skulker's orchestrated contest ends in a tie, he handcuffs Danny and Valerie and hunts them both through the Ghost Zone. In order to survive, Danny and Valerie learn to let go of their mutual dislike and cooperate with each other - which may just affect their relationship in the real world. Or, not.

When Vlad Masters' ghost portal explodes, he schemes to replace it by stealing Jack Fenton's portal. As a distraction, Vlad anonymously offers a million dollar bounty to eliminate Danny Phantom. As ghost hunters from around the world gather in Amity Park to hunt the ghost kid, Danny sacrifices himself to Jack - both to win the prize money for Dad and to bolster Jack's inept reputation, which embarrasses Danny. However, when his family's life is put in jeopardy, Jack needs no help from Danny to save the day on his own.

Sam rebels when her overprotective parents forbid her from attending the strange Goth circus that's come to town. Little does she know that the circus performers are ghosts, under the mystical control of the creepy ringmaster named Freakshow, who also uses the ghosts to loot the town. When Danny falls under Freakshow's spell and joins the circus - and the robbery spree - Sam must operate under the radar to destroy Freakshow's magic crystal ball, free Danny and get grounded, big-time.

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.