The Brian Lewis Christmas Tree Farm is where Principal Lewis initiates a scheme to poison all of Langley Falls in "The Hall Monitor and the Lunch Lady".
While Steve and Klaus investigate the cause of several students becoming ill during lunch, they discover a large amount of sawdust being stored in the kitchen. Working with Hank Turlington, who is also working undercover on the case as a female teacher and suspects a connection with the hall monitors that Principal Lewis appoints. With his help, Steve is sent to the Chimdale Juvenile Detention Center, where he becomes friends with the brother of head of the hall monitors and manages to join the crew after getting out. His work impresses the gang, so they introduce him to Principal Lewis, who tests him by having him vandalize a pet store.
Having gained his trust, he is invited to a dinner with Lewis and the hall monitors and wears a wire to record the conversation. He also learns that Lewis had purchased a Christmas Tree farm but was disappointed that it only generated money one month out of the year. Looking to expand the need for sawdust generated by his farm, he had been poisoning the students and plans on doing the same to the entire town.
When they try to take their evidence to Turlington, they find he has been killed. The hall monitors are invited out to Lewis' Christmas tree farm for the poisoning, but he also reveals that he knows there's a mole. Having taken Turlington's phone, he dials up Steve. Facing capture, Steve uses the power of his leg muscles that he built up while in juvie to leap over the gang and drink the poison himself. Klaus makes a timely arrival with the former lunch ladies and they rout the gang. Steve is saved by a salsbury gravy IV as Klaus informs him that Lewis got away.