• Original air date: September 27, 2003
• Writer: Jeffrey Alan Schechter
• Director: Stefan Scaini

  Guest Stars:
  Actor's name	Character played
  Talia Schlanger	Madison
  John Stocker	voice of the furnace
  Christopher Tai	Tyler

Marshall has a cold and, in the opinion of everyone else, is acting irresponsible about it. Marshall doesn't have time to worry about that though because be is currently in the business of installing wireless network cards into the computers of the school. While working on a computer, he sneezes on the main server's circuits, which are open. The discs start up, shooting electrical currents throughout the system across the wireless network, making its way into the school's furnace and the furnace begins sneezing.

The next morning, one of Marshall's customers, Tyler, comes to Marshall complaining his computer doesn't work and to refund his money, Marshall offers to fix it instead.
Meanwhile, Professor Z's office is super hot.

There is loud sneezing going on around the school. In the halls, Principal Durst complains to the Janitor that her office is as cold as an igloo.

More of the computer's Marshall worked on continue to not work. Loud sneezing continues throughout the school. Upstairs, green goo leaks from the ceiling down the walls and into puddles on the floor. The school rumbles at the sound to a sneeze. In the basement, the furnace is getting worse, its temperature and pressure are rising and goo begins to coming from it too.
The Vaughn and Corrine makes a map of the chain of infection to lead them to the center of the outbreak, Josie and Lucas force Marshall to take medicine, and Professor Z stalls Principal Durst because she wants to evacuate the school (at one point, they use a lamp for warmth because it is so cold in her office).

Corrine and Vaughn find out Marshall's wireless network server is the source of the spread of Marshall's cold. They open it up again and goo pours out. There is a loud sneeze and the school shakes. Josie says it came from the basement and Vaughn, Corrine, and Professor Z go down to check the boiler, discovering it's temperature and pressure are too high. The furnace will blow up if it gets worse. Josie and Lucas unplug the server, to Marshall's dismay he won't be allowed to plug it back in. But that doesn't stop the rise in pressure in the furnace and they resolve to burn the server in the furnace for the heat to kill off the germs. After putting the server into the furnace, the furnace returns to normal.

Marshall is made to clean up the school; all his customers want refunds. In the last scene, the Janitor sits with the furnace, caring for it.

Episode notes:

• Janitor's secret message: "Tyler will become a threat to them all" and "The school is not cured."
• Principal Durst says that the Blake Holsey High building was built over 150 years ago.
• Josie says that there is a vortex in the basement. In all other episodes, the vortex is in Professor Z's office (when opened naturally, unlike in Wormhole²).
• When everyone is in Lucas and Marshall's room, when Josie says the sneeze comes from the basement, the plug to the server is away from the desk the server is on, but in the scene where Josie unplugs it the plug and its outlet are under the table.
• When everyone is in Lucas and Marshall's room, when Josie says the sneeze comes from the basement, when the sneeze shakes the school, none of the medicine viles on the wheeled cart shake.

Personal thoughts:
Again with this episode, it was disappointing to see no progress made on the show plot.
On the plus side, this episode was packed with humor. Even the things not said - how could you not laugh at the Janitor's expressions and his needing to get bigger mops or Principal Durst and Professor Z trying to keep warm in Principal Durst's office? The irony as well - Professor Z telling Principal Durst there isn't anything wrong with Blake Holsey High.
Rating: 6/10