The teens at Clone High begin smoking raisins, which sets them on a groovy, music-filled trip, so Principal Scudworth and the PTA develop a plan to fence in the students.
A local pork producer is impressed by Luanne, who goes to his home for a job interview but comes away as his girlfriend.
Dale exterminates at the Mega Lo Mart, thanks to an endorsement from a reluctant Hank.
Johnny struggles to rescue four teens trapped in a collapsing mine, all while reliving - and in some way trying to redeem - sins from his family's past.
While Alliance counterintelligence head Ariana Kane tracks Sydney in order to catch her fugitive father, Jack elicits Irina's help in finding Sloane's blackmailer. Meanwhile, Sydney and Vaughn risk exposing their covers to SD-6 when they share a romantic dinner together while on a case in France.
After kidnapping Phoebe, Cole sends a shapeshifter to assume Phoebe's identity to help him manipulate Piper and Paige into giving him ownership of the Manor, allowing him access to the powerful Nexus located beneath the house. Meanwhile, Phoebe plans her escape, and Cole gets Paige arrested and ensures that Piper's club fails to pass health inspections in order to keep them distracted.
When Kif gets pregnant, Amy questions her readiness to become a parent.
Vernon and David are travelling in a tanker which overturns spilling its load. Vernon is taken to hospital with memory loss and David claims not to know what they were carrying. The police discover that the tanker has false number plates and its contents are contaminating the water supply.
Personal grief has to be put aside when brilliant detective Red Metcalfe is faced with a series of grisly and sadistic killings. Each body provides a taunting clue to the murder method to come and the police team and their families could be next on the hit list.
Black Hole energy interferes once again. While the Janitor senses something will soon occur, the members of the Science Club continue their exploration of the paranormal phenomenon which afflicts the school. But secrets concerning strange phenomenon at BHH are given to Victor Pearson by Vaughn. As a result, Vaughn is in a bad mood. Which literally produces a strange occurrence! Do his emotions cause the catastrophic storm above his head? How will Vaughn make the gray clouds, which follow him all the time, disappear for good?
Children unwittingly reopen an ancient battle between Autobots and Decepticons.
When Animology sweeps over the school, Kim tries to avoid it, but she gives into the fad. Meanwhile, the Seniors start their most dangerous plot to date.
Lenny renews his duel of wits with John, kidnapping Lt. Avery and sending a series of cryptic clues with a fatal deadline. A new captain makes things hard for John and he and Digger go off on their own to hunt down the killer. John meets up with Frank and they figure both that the police are on the wrong trail going into a booby trap and where Lenny really is. But Frank accidentally shoots John, killing him and letting Lenny escape. It's a ruse to draw Lenny out at the cemetery with no one in the way, one that (more or less) works. We do find out that Lenny branded himself with John's mark and didn't have any deep connection to him.
The team is called into battle unexpectedly when the Asgard homeworld is overrun by Replicators -- which have evolved into a startling new form.
JT the class clown gets in trouble and spends the week afterschool with the hot science teacher Ms. Haztilakos but along the way he finds that she is a person not just a hot teacher and he earns her respect. Jimmy and Spinner are starting to tell the truth forever and end up with unexpected results.
Holly has a major crush on a cute college guy named Evan and he's been coming in everyday at "Copy That" to get some coffee but Holly gets a chance to actually know him when she "accidentially" takes Evan's cell phone and gets invited to a college party to swap phones. Gary wants to come too, but Holly doesn't want him to interfere. However, despite Holly's wishes, Gary shows up at the party as a co-ed to get in with the college girls. Meanwhile, Val starts to get a little competitive at Scrabble.
After Oswald fails his nursing school exam, Drew feels bad and helps him get a job at the web site. Oswald finds a way to nearly destroy the entire business. He ends up being reassigned to a job that he (sort of) knows how to do--delivering packages. Mimi repeatedly sucks up to Traylor in an attempt to get on her good side after trying to kill her.
The Delightful Children From Down The Lane attack Sector V's headquarters with an infestation of hair-eating lice. After the KND find out they don't like nacho cheese, they decide to shoot nacho cheese at them to get rid of them.
After accidentally returning to Earth, Crichton discovers it he is in 1985 and he has altered the time line, causing his father to be scheduled to fly on the doomed shuttle 'Challenger'.
Barnaby investigates a death which looks very much like suicide. The dead man was a troubed and depressed gambler on a losing streak, but Barnaby's nose tells him to look for a murderer. During the investigation he recognizes someone from his past, in the shape of Dr Jane Moore.