Clark comes to the aid of his high school class after they are held hostage at LuthorCorp by a former janitor who claims to have been sickened by a project he worked on at the plant.

Who's Earl?Earl was a farm hand for the Kents until he took a full-time job at LuthorCorp working as a janitor on level 3. The experimental fertilizer project on level 3 ended in an explosion. Seems they were spraying kryptonite over corn to make it grow. After the explosion, Earl was left with an ailment that caused him to break out into intensely violent seizures. Level 3 was closed, the elevator to it sealed, and Lionel Luthor denies it ever existed. Even Lex doesn't know about it. In an attempt to see Lionel about getting access to level 3 for a potential cure, Earl accidentally kills a security guard. Now he's wanted for murder. He flees and hides out in the Kent's barn, waiting to talk to Clark's father.

What's up with Clark? His parents go to Metropolis for the weekend to celebrate their anniversary. Clark intends to throw a small party that turns into a messy bash. He is called away from the house to the barn where Lana and Whitney encountered a violent shaking. Clark and Whitney discover Earl hiding there. When Earl gets jiggy, Clark tries to help him, but Earl's kryptonite poisoning affects Clark and he is unable to get near him without getting sick himself. Clark visits Earl in the hospital and learns of level 3. Conveniently Clark and his class have a field trip to LuthorCorp the next day and Clark vows to investigate.

What's up with Chloe? She's embarrassed when the LuthorCorp tour guide turns out to be her dad who cracks corny fertilizer jokes during the tour. She, her dad, and the rest of the class is taken hostage after Earl breaks out of the hospital and back into LuthorCorp.

What's up with the Kents? They return early from their anniversary celebration after calling Clark six times and getting no response. They watch Clark hyper clean their house. Jonathan learns of Earl's plight and vows to help. He and Martha learn of the hostage situation and head to the plant. They run into Lionel and argue with him over how the hostage situation is being handled.

What's up with Lex? He has no idea there is a level 3 at his own plant. He volunteers to go into the plant to negotiate the release of the students. He convinces Earl he'll show him level 3 if he will release the hostages.

How does it all end? Clark breaks away from the hostage situation to see if he can find level 3. Using his X-ray vision, he sees an elevator behind a brick wall. He smashes the wall and brings Earl and a stunned Lex to level 3. Level 3 is now an empty warehouse. While the three are walking on a catwalk above the warehouse, Earl starts to shake and the catwalk breaks away leaving him and Lex hanging. Clark risks his life to grab Earl: Lex is clinging to Earl's legs. Clark barely manages to save them. Lex asks him how he did it, and Clark says "adrenaline, I guess." Lionel tells the media level 3 is just a forgotten warehouse and Earl is a sick man. Lex cuts in and tells the media that LuthorCorp is all about family and that's why they'll be helping Earl get well.