A half-ghostly nerd takes over the biggest nerd in school and tries to kill all the people that picked on the nerd he's taken over and falls in love with Valerie in the process. Now, Danny, Tucker, and Sam must find out how to get Poindexter out of the nerd and back in the mirror, in which he came.
The episode starts off with Dash pushing around the weirdest, biggest, and most picked on nerd in school, Mark. After school, Mark is walking home, talking to himself about his miserable life. Out of nowhere, he hears whispering and a voice (Danny Phantom's enemy, Poindexter) tells him not to feel sad. Mark hears the voice coming from a broken mirror. He picks it up and tells him he'll take care of his problem and green smoke comes from the mirror and takes over Mark.
Danny and Tucker are nailing posters booths for Amity Park's Fall Fest, but Tucker is using a hammer and Danny is using his enhanced strength to nail it with his hands. Dash tries to talk to Danny and apologizes, but only so Danny will give him back Valerie's necklace. Danny ignores the apology and tells him he lost the necklace. Angry, Dash rides home, when his car is flipped over and is pouring gasoline near a fire, knocking out Dash and it shows the possessed Mark walking away.
As Danny, Tucker, and Sam are walking to Danny's house, they see Dash knocked out and a fire traveling to Dash's truck. Danny super speeds to Dash and turns Dash and himself intangible, right as the fire goes off and the fire goes right through them. Tucker and Sam check to see if Danny's alright and he is, but he has some bruises from the debrief. While the team tries to figure out what happened, Vlad visits Valerie and asks her if she knew where here boyfriend was and why he had rope surrounding Danny Friday, making her suspicious.
At school, Mark tries to hit on Valerie by asking her to tutor him. Not wanting to be rude, she says yes. Mark (Poindexter), leaves as Dash walks up. Valerie asks him where he was before his game on Friday. He says he was warming up with the team. Knowing he's lying, she tells him she knows what he did to Danny, so she goes to see him. Mark (Poindexter) tries to talk Valerie, but she tells him she needs to talk to Danny and that she'll need a rain check on their study session, making him mad at Danny.
Later that night at Danny's house, The lights go off, so Tucker goes down to the lab to get flashlights. As he walks up, Mark(Poindexter) pushes him down. Danny hears Tucker yelling and super speeds to catch him while he speeds down to help tucker he tries to throw Mark(Poindexter), but he also has enhanced speed and speeds away.
While Dash apologizes to Valerie, Mark(Poindexter) rushes in knocks them out and takes Valerie. Danny and the team check the route he walks home on and they hear the whispering from the mirror and they pick it up and see a black and white, old fashioned version of their school, knowing that Mark was taken over by something there Danny speeds to find him.
Danny finds Dash waking up and Dash tells him that Mark took Valerie. Mark takes the mirror from Tucker and Sam and throws them, but Danny shows up and catches them. Poindexter escapes Mark's body and tries to escape with Valerie to his world in the mirror, but Danny stops him and traps him in the mirror. Before Poindexter escapes, Danny shatters the mirror and takes Valerie and the team home.
- Danny Phantom's (former) enemy, Sidney Poindexter, makes his first appearance.
- "Pilot" -- Episode 1
- "Invisible" -- Episode 3