"13" is the fourteenth episode of the TV-series Danny Phantom.
Danny fights off a ghost squid, wolf, and cobra all in the course of one night. Distressed over all the ghosts coming out at once, Danny wonders why there's so many to begin with.
The answer is given when Jack tests his new genetic lock that opens the Fenton Ghost Portal only by the press of a button through a Fenton family member. Unfortunately Jack (while showing it off to Maddie and Jazz) pushes it one too many times, releasing one ghost per button press. A ghost named Johnny 13 and his girlfriend Kitty race for the portal on his motorcycle.
Telling his shadow, an intelligent entity known simply as Shadow, to keep the portal open, Johnny races in before it closes. Unfortunately, they barely just make it while the portal closes and zaps Kitty. Unable to maintain a solid form, she spreads her energy to her jacket, ring, and scarf, telling Johnny to find a host to wear it so she can conceal herself in that body. Kitty heads back to the Ghost Zone while Johnny vows to find a body, which he quickly does when he eyes Jazz upon entering Earth.
The carnival is approaching and Tucker manages to ask a girl out. Unfortunately his technology is off putting and she leaves, viewing him as a techno geek and upsetting him. Meanwhile, Danny encounters Johnny 13 and loses the battle as well as the ghosts he caught previously when Johnny's Shadow destroys a lamp post that hits the Thermos as Danny rolls to safety.
At the carnival, Danny tells Sam and Tucker about his recent encounter with Johnny. Sam asks Tucker to use his PDA only for him to be picked on by Dash and Kwan. Tucker has finally had it with being labeled a "techno geek" so instead of helping, he tries to find another nickname for himself.
Meanwhile, Johnny sends his Shadow to move a truck (which Tucker was standing next to), making it crash towards the roller coaster support railings. Danny rescues the inhabitants in the roller coaster, but the coaster itself heads straight for Jazz.
Occupied with the rescues, Danny unfortunately doesn't make it in time, but luckily Johnny saves her life. Immediately she expresses gratitude and develops a crush on him.
Johnny then offers Jazz Kitty's scarf while Danny watches the two, unhappy with their sudden budding relationship. Tucker in the meantime faces the problem of now being labeled "Bad Luck Tuck" by his peers after walking under a ladder and into Dash's fist.
Danny and Jazz's roles are reversed when he ends up being the overprotective sibling over her due to their rambunctious decisions. As such, he is absolutely livid when he sees Johnny's bike parked near his home, and even more so when Johnny nearly kisses Jazz (after offering her Kitty's jacket).
Wanting to be alone together, Jazz takes Johnny to the basement where she shows off the Fenton Ghost Portal. Jack and Maddie come in after Danny rats her out, stating unauthorized people are not allowed in the basement, prompting Johnny to leave.
By school the next day, Danny is concerned over being in the same thought bubble as his parents while Tucker tries to convince others he is not bad luck, only for Johnny's Shadow to cause even more for him by making him accidentally toss his spoon into a bee's hive, causing nearly everyone in school to be stung. After school, Danny sees Jazz drive off with Johnny on his bike and gives chase.
Johnny spots Danny and sends his Shadow to attack, the dark creature ultimately trying to suffocate him. Johnny in the meantime offers Jazz Kitty's ring, asking her to be "his girl."
Danny manages to break free from the Shadow through his ecto ray, figuring out bright light weakens it. He heads to the local movie theater where Sam suggests to Tucker to get a new image to reduce his "bad luck" status at school. Meanwhile, Danny manages to send the Shadow away through the light of a movie projector.
Johnny again asks Jazz about the ring, which she is thrilled to have. Just as he almost slips it on her, Danny flies by, turns human, and lands right in front of the two. Upset that she was spied on, Jazz rats him out to Jack and Maddie who pretend to punish Danny but secretly praise him for spying, not trusting Johnny as well.
The next day, Tucker is now a goth, thanks to Sam, but refuses to wear the make-up associated with it while Danny continues worrying that he is becoming like his parents and that his sister is dating a ghost.
Later that night, Jazz sneaks Johnny into her house and to the basement where he once again tries to give her the ring. Danny interrupts and shakes Jazz to her senses, causing the jacket and scarf she was wearing to loosen.
Johnny sends his Shadow to distract Danny while he forcefully slips the ring and clothes back on Jazz then makes her push the genetic lock button to open the portal where Kitty awaits. There, she absorbs the power to take over Jazz's body. Danny goes ghost and manages to take out the ring, causing the takeover to cancel itself out. Danny flies off with the ring and the Shadow gives chase.
Elsewhere, Tucker grows sick of the goth look and decides his original role as a techno geek is much better suited to himself, which Sam agrees to, having used reverse psychology to return Tucker back to the role he was meant to be in. They then get a call from Danny who needs Tucker's help.
Back at Fenton Works, Johnny locks up Jack and Maddie in their own room when they wake up, only to be freed when Danny flies through the door and the Shadow follows. Danny flies to the basement and gets the Shadow to destroy the Genetic Lock machine, closing the Fenton Ghost Portal. Angry, Johnny and his Shadow reunite and give chase to the Ghost Boy.
Danny lures Johnny's Shadow to a stadium where, with Tucker's help, he manages to light up the entire place making the Shadow disappear and for Danny to suck up a helpless Johnny. Jack and Maddie come afterwards, disappointed in not being able to deliver their own blow to him.
Jazz thanks her brother while Jack and Maddie admire Danny's similarity to them. As a reward, Jack gives Danny one of his jumpsuits, which is obviously too oversized for him, to wear by school the next day.
Unfortunately, this also makes him yet again a target for Dash and his friends, much to a relieved Tucker because he's not the new target anymore. In the end, Danny decides he needs a new image and asks Tucker if he can borrow his PDA, but Tucker tells him to get his own, making him have a bad ending.
- David Kaufman as Danny Fenton/Phantom
- Rob Paulsen as Jack Fenton
- Kath Soucie as Maddie Fenton; Concessions Kid
- Rickey D'Shon Collins as Tucker Foley
- Grey DeLisle as Sam Manson; Kid
- Scott Bullock as Dash Baxter; Clown Artist
- James Sie as Kwan
- Colleen O'Shaughnessey as Jazz Fenton; Girl
- Chynna Phillips as Kitty
- William Baldwin as Johnny 13
- Danny Phantom: Season 1
- Danny Phantom: Season 1
- Nickelodeon Fool-Proof Fun
- Many of the ghosts seen escaping at the beginning of the episode were among the large group of ghosts who fled from the Ghost Zone at the beginning of "Reign Storm."
- Allusions: See List of allusions
- Goofs: See List of goofs
- At the start of the episode, Ember is among the ghosts in a line waiting their turn to enter the Fenton Ghost Portal repeatedly being opened and closed by the DNA lock.
- This is one of the rare times Tucker is seen without glasses.
- When Danny takes the ring from Kitty, he calls Johnny "Freakshow" as a possible reference to one of his future enemies.
- This is the last episode to premiere in 2004.
- According to the credits, this is the last episode produced in 2003.
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