This episode starts off with Sam rushing Tucker and Danny because they are going to be late for school. However, they are too wrapped up in the environment-unfriendly Gi-Normo 6000: an SUV. Sam really wishes that somebody would destroy these environment-ruining trucks, but Tucker reveals that this would not be the first time that her bad ideas got Danny into trouble. Then they reminisce to the time before the accident and how it happened. Desiree hears Sam's wish and grants it, by making a giant plastic cow come to life. The cow destroys the truck and covers Danny and Tucker in milk.
Then, Sam, Danny, and Tucker are walking to school. Danny makes himself and Tucker intangible so that the milk slides off. Then Sam sees a poster for "Tinity of Doom," a horror film featuring three of the most popular horror film characters: Femalien, Nightmerica, and Terminatra. Danny promised her that they would all go on Friday. Suddenly, Paulina comes near Danny, Sam, and Tucker with invitations to her 15th birthday party. Paulina explains that she really wants Inviso-Bill to be there and because he shows up wherever Danny shows up, she felt that she had no choice but to invite Danny and his friends. Danny and Tucker are ecstatic but Sam reminds them that Paulina's party is on Friday, the same day as the premiere of Trinity of Doom, and the tickets are nonrefundable. However, Sam caves in and lets them all go to Paulina's party instead, but secretly hopes that something will happen to Paulina so that the party would get canceled, but she doesn't exactly "wish" it. Desiree makes it happen, anyway, since Sam did say the word "wish."
Later at school in Mr. Lancer's astronomy he is explaining about how the meteor shower could kill all the students, if they just stand there wishing. Then, Paulina explains that her father told her that the meteors are falling just for her and that she would wish to meet the ghost boy. Dash wishes that he had extra arms to catch more footballs and to hurt Danny, then he punches him in the arm. Suddenly, Danny's ghost sense goes off and Femalien appears and screeches Paulina's name. Mr. Lancer tries to scare the monster away but it doesn't work, so everybody just runs in frenzy. Danny goes ghost and chases after Femalien who is chasing Paulina. Danny and Femalien both go intangible and phase through the floor, right when Paulina was going to invite Inviso-Bill to her party. Danny demands to know who sent Femalien after Paulina, and the Femalien screeches Sam's name.
During lunch, Danny explains to Sam and Tucker how the monster knew Sam's name and makes her wear the Specter Deflector and tells her to lay low.
Later outside, Danny sees Terminatra chasing after Paulina, who is on her moped. Danny has to go ghost. Paulina is motoring away from Terminatra with her pink dress that she got back from the cleaners and exclaims that this is the worst birthday week ever, then she immediately says it's not when she sees the ghost boy appear. Paulina invites the ghost boy to her party, so that she can uninvite Danny Fenton and his friends. Suddenly, Terminatra pushes Danny into the water, but Sam saves him with the Specter Deflector. As Terminatra is melting in the water, she says, "Sam." Danny and Sam then fight about how Sam is connected to the monsters even though Sam saved his life. Then Sam says that they are some days that she wishes that she never met Danny. Desiree reveals her new stronger self to Danny and grants Sam's wish.
The next day at school, Sam greets Danny, but Danny doesn't know her anymore because of Sam's wish. Sam thinks that Danny is just being mean, and then Tucker suddenly hits on her. Then, Mikey, who has just been stuffed in Dash's locker wishes that somebody would show him and Kwan how it feels like to be stuffed into a locker. Desiree, of course, grants his wish, turning him into a monster. Desiree comes near Danny and Tucker and they both tremble in fear when she says "Boo." Sam wonders why Danny isn't going ghost, and Danny claims that he has no idea what she's talking about and leave the vicinity. Sam realizes that Desiree granted her wish that she never met Danny.
As Danny is walking home, Sam explains how they used to be best friends and how he had ghost powers. But Danny refuses to believe this and Sam realizes that the only way to get through the thick head of a fourteen year old boy is to dress attractively.
Sam appears at Nasty Burger wearing colorful clothing. Danny and Tucker are both turned on by her. Then, Nightmerica breaks into the Nasty Burger. Sam then uses the Specter Deflector and the Jack-A-Nine-Tails to defeat her. After Nightmerica is defeated, Danny becomes interested in what Sam has to say. Sam then opens her diary filled with pictures and tries to get Danny to understand the meaning in them. When Danny finally understands, Sam explains how a few months ago, she convinced Danny to go into the Fenton Portal and she explains how he obtained ghostly superpowers. Sam rips off her colorful clothes, and reveals her trademark Goth clothes underneath them, and they all rush to Danny's house.
Danny, Sam, and Tucker are in the lab, with Tucker keeping guard. Then Sam starts to recreate the incident, by setting the clocks to the time it was when it happened. She gives Danny his jumpsuit and removes the sticker of Jack on it, and places and unknown sticker on his jumpsuit. Danny goes into the Fenton Portal, presses the "on" button, and actuates the portal. The ectoplasmic energy fuses with his DNA, giving him a ghost-human hybrid genetic structure. Danny comes out of the portal and goes intangible in Sam's hands and Danny realizes that he's a ghost and his new emblem is shown.
Suddenly, Jack comes downstairs and sees his son and Sam having a "fake-out make-out." Jack demands to know who that girl is (as he was also affected by Sam's wish), and she claims that her name is Paulina, and then Jack forbids Danny from seeing "Paulina" again.
The scene switches back at school, where Danny is losing control of his newly obtained ghost powers. Suddenly, Sam realizes that Desiree wants to grant the wishes people are going to make during the meteor shower at Paulina's party. Then, Danny accidentally phases through the floor and Lancer yells at him.
Later, at Paulina's 15th birthday party, everybody is dancing while Sam is looking at the party through her binoculars. When the meteor shower comes, all the partygoers start making wishes, but Sam tells Tucker and Danny not to, but Tucker does it anyway. Tucker wishes for a Gi-Normo 6000. The truck appears to be harmless, but then it comes to life. Danny tries to fight Desiree but is unsuccessful since she is getting more powerful with the wishes she grants. So, Sam wishes that she never fought with Danny, that she, Danny, and Tucker remembered everything, but Danny's costume to stay the way it is -- with the new "DP" emblem on it. Danny soon regains his memory and catches Desiree in the Fenton Thermos. Danny decides to keep his promise, and they all go see Trinity of Doom. Danny and Sam apologize to each other at the movie theaters and it's like the fight never happened.