He finds the entire town of Amity Park is under the same ailment due to Nocturn, the ghost of sleep who is sucking up their dreams to increase in power. Danny must wake his friends and sister up in order to stop this madness.
Danny Fenton walks through the school cafeteria feeling very cheerful; he got an "A+" on his science test, is the star of the football team, is respected by even the popular kids, and is the love of Sam's life. His happiness is cut short when the Fright Knight appears. Immediately the kids turn their attention towards Danny, demanding he use his ghost powers to stop the ghost.
Danny is shocked that they know his secret, but he quickly transforms and easily defeats the knight. He returns to the cafeteria, greeted by cheers from the students. Danny sits down next to Sam and they lean toward each other, but just as they are about to kiss, the vision fizzles away. Danny suddenly wakes up on a floating piece of rock in the Ghost Zone, destroying a metal helmet on his head in the process.
Realizing that the entire event was nothing but a dream, Danny flashbacks to the previous night when he encountered various ghosts with stitched eyes and a mysterious dark figure commanding them. Danny flies home to Fenton Works to look for clues and is met with complete silence. Much to his shock, his entire family is fast asleep, wearing the same metal helmets he had.
Trying to remove them does little, so he flies to the Ops Center to check the house’s security cameras. In the recordings, he sees the same ghosts with stitched eyes as they phase into his home and put the Fenton family to sleep, leaving the dark figure to put the helmets on them.
Danny flies out to his friends' houses, only to find them asleep under the helmets as well. Danny quickly finds that the entire town of Amity Park is under the same sleep spell as his friends and family. Using Tucker’s holographic security camera, he sees the dark creature in full—a new ghost. Suspecting that Vlad is behind it all, Danny flies to Vlad's manor only to find Vlad asleep as well.Before he can react, he meets again with the ghosts with stitched eyes and the dark creature. Danny suddenly remembers him as someone he fought in the previous night; Danny lost the battle, was put to sleep, and sent to the Ghost Zone with one of the helmets.
The dark creature shackles Danny down on a table, planning to send him back into the Ghost Zone.
The dark being then introduces himself as Nocturn, ghost of sleep and dreams, and his minions, the Sleepwalkers; he travels from town to town sucking out the energy from peoples' dreams, which increases his strength.
Danny breaks free from Nocturn's restraints using his ice powers and tries in vain to stop him, but with Nocturn's strength, Sleepwalkers easily gang up on him. Danny barely freezes Nocturn in time to fly away, leaving the sleep ghost to recharge. Danny needs allies, but he is unable to remove his friends' helmets.
He remembers that his helmet was destroyed when he was shocked in his dream, and figures he needs to trigger a similar shock to wake his friends. Possessing Tucker first, Danny enters Tucker's dream and finds himself in a lavish manor.
Inside, Tucker is surrounded by twins of popular Casper High student Star, with Danny Fenton as the janitor. Just as Tucker is about to kiss one of the Stars, Danny interrupts and takes her place, causing Tucker to wake up from that brief nightmare.
Heading over to Sam, Danny enters her dream, which he soon finds out was almost exactly like his own, right down to the setting and events. Danny quickly overshadows Dash and goes ghost in Dash's body, causing Sam to wake up screaming.
They finally fly over to Jazz, and Danny changes her dream of being a Yale professor to make it so that she was married to Dash--much to her horror. Using Tucker’s technology, they find Nocturn’s hideout in the local mattress warehouse near the harbor, with a giant antennae on top absorbing the dream energy of the sleeping Amity Park residents. They head inside to find Nocturn recharging inside a giant machine connected to the antennae.
Unable to crack the machine open, Danny declares he needs to possess Nocturn like he did with his friends and sister to wake him up. Sam is quick to volunteer to help him, leaving Tucker and Jazz to prevent any Sleepwalkers from coming their way Within Nocturn’s dream, Nocturn is already all-powerful.
No matter what Danny and Sam do to try to stop him, they can do little due to his power level. Tucker however saves the day by jamming the antenna’s frequency, stopping the flow of dream energy and weakening Nocturn enough for Danny to force him awake. He is easily defeated afterwards.
With Nocturn gone, the four sit, relax, and discuss their dreams; when they get to the subject of Danny's and Sam’s, the two blush and deny anything, saying they don't remember what their dreams were.
- While debating on how to wake Tucker up, Danny mentions that he has overshadowed Tucker before, such as he does in "Parental Bonding."
- Tucker's dream of being better than Danny is another sign of Tucker's occasional envy towards Danny, first seen in "What You Want."
- Allusions: See List of allusions
- Goofs: See List of goofs
- Danny spends most of his time in this episode in ghost form. Even after he and his friends had defeated Nocturn, he still didn't change back to human form. He only appears in his human form in his and his friends' dreams and briefly at his house.
- This episode has the most screen time of Danny in which he uses his ice powers. He uses his ice powers even more than in "Urban Jungle," where ice powers were the central plot point.
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