Hector, Dee, and Terrence are three students who think their school's lunch lady, Betty, has a boring life. But when their favorite teacher, Mr. Kropotkin, is replaced by a strange new substitute, they discover Betty's incredible secret. Using her hidden gadgets—from fish stick nunchucks to a spatu-copter—Lunch Lady transforms into a superhero to investigate. The kids join her mission to uncover if the suspicious substitute is actually a cyborg planning something sinister for the school.