|“This way, I produce a whole new breed of monsters which the Knights will never expect. Ugh, coming from down deep. That felt like a good batch.”|
“Well, you're definitely sick. I guess the plan is working so far.”
|— The Book of Monsters and Jestro|
The Nexo Knights await the arrival of King and Queen Halbert in Cleanington. As the royal hovercoach arrives FancyPants informs everyone to be on their best behaviours as it is the first dinner between the royal couple and the Mayor in ten years.
Macy complains about having to fulfil her royal duties. The royal couple arrive and are greeted by Roger the Scrubber who sends them off to their chambers before the banquet. Macy offers Clay anything to get out of her royal duties but he refuses and sends her on her way.
Jestro and the Book of Monsters arrive in Snottingham, the coldest place in the kingdom where the residents have an unusual obsession with getting ill. They go to Ye Olde Runny Nose Tavern. The Book of Monsters orders a strange dish called the Snotheiser special which has the ability to make a person sick if eaten. The Book consumes so he can make a whole new breed of sick monsters which the Knights will never expect.
On honor guard duty at the banquet, the other Knights are growing restless. They decide to relieve their boredom by making funny faces at each other, eventually getting Macy to join in as well. Mayor Coughmeyer arrives to inform everyone that Snottingham is under attack. Macy is initially stopped from leaving by her father but he lets her go on the conditions that she not stay out too late and keeps fighting to a minimum.
After a horrible pre-fight line from Clay, the Nexo Knights and Jestro's forces battle. The Knights note that the monsters don't seem to be at their best. As they fight on, the monsters sneeze on them. The Knights attempt the Nexo Power Dragon's Claw but the signal doesn't go through. After some old-fashioned fighting the monsters retreat. The knights walk off, covered in monster mucus, their shields flickering green as they go.
On the Evil Mobile, the Book is being held over a lava bath to help him recover. With their initial plan in action, the pair can proceed with their real plan; capturing the King and Queen while the Knights are too weak to stop them.
In the Fortrex, the Knights are beginning to show signs of illness. While they all have general pain and coughs they have wildly different symptoms; Clay is hallucinating, Aaron is dizzy and uncoordinated, Macy has intense pain from everything she touches and Axl isn't hungry. Apart from a supposed lack of luster in his hair, Lance is otherwise fine. Ava deduces that they have the Snottingham Cold, an obscure illness with bizarre symptoms, and tells them to stay in bed while she upgrades Merlok 2.0’s antivirus software so the Cold doesn't spread from their shields to his program.
In Cleanington the villagers are sweeping but flee in fear when Jestro and his monsters arrive, leaving the royal couple and the mayors unguarded. The Knights arrive and try to fight but are being easily beaten. Ava tries to send the Nexo Power Serpent of Recovery but this fails to go through as well. Burnzie and Sparkks capture the King and Queen. Ava sends through the Nexo Power again now with a booster pack of antivirus programs. The Knights receive the Power Serpent of Antivirus which clears the virus in their shields and cures their colds. Clay and Macy save the royal couple while the others fight off the retreating monsters.
Mayor Roger congratulates the Knights on saving his town. The rest of the villagers would be there too but the Knights passed them the Snottingham Cold. Mayor Coughmeyer offers the group some fresh snot-heisers which they greatly refuse.
In the downtime room most of the Knights are cleaning the room, except for Lance who is sat on the couch pretending to be in pain. Clay comes over and tells him that if he's not going to help, he should at least do something productive. Lance takes this as a sign to get his hair done after all the fighting he's been through and calls Dennis for a haircut.
- Aaron Fox - Alessandro Juliani
- Ava Prentis - Marÿke Hendrikse
- Axl - Brian Drummond
- Burnzie - Giles Panton
- Book of Monsters - Mark Oliver
- Clay Moorington - Giles Panton
- Coughmeyer - Colin Murdock
- Haute FancyPants - Brian Drummond
- Jestro - Vincent Tong
- King Halbert - Brian Drummond
- Lance Richmond - Ian Hanlin
- Macy Halbert - Erin Mathews
- Merlok 2.0 - Brian Drummond
- Queen Halbert - Nicole Oliver
- Roger the Scrubber - Vincent Tong
- Squirebots - Brian Drummond
- Main article: Saturday Knight Fever/Transcript
- Nexo Power: Serpent of Antivirus
- The Nexo Powers Dragon's Claw and Serpent of Recovery were attempted.
- The title of the episode is a pun on the 1977 movie Saturday Night Fever.
- This is the first episode where Robin doesn't make an appearance.