There is a scoundrel going around town and tagging buildings, the mysterious El Barto. When El Barto tags the school, Principal Skinner vows to capture him. Groundskeeper Willie suspects that it might be Bart, so he proposes a plan to Skinner. Skinner has a light meeting with Bart and he gets suspicious of Bart, so now he moves onto a more intense form of interrogation. Bart is captured, tied to a chair and now the interrogation begins. After some time, Skinner and Willie pull out their trump card. They make out in front of Bart. Bart, completely grossed out by the act, breaks and confesses to being El Bart. He is thrown in detention, and is scarred for life.