12-year old Cornelius Fillmore, a juvenile delinquent with a record, was caught raiding the school's new chalk shipment. He was arrested and given a choice by the safety patrol officer who caught him, either help him solve another case or spend the rest of middle school in detention. Fillmore decided to help out and he eventually decided to join up with the safety patrol. The show is based around him and his partner Ingrid Third at X Middle School, which is located in the suburbs of Minneapolis and St. Paul. The show's format parodies that of hard-boiled police dramas. X's safety patrol is much more actively involved in student behavior than a typical school's safety patrol, and officers often seem to spend more time patrolling than actually attending class, although they can be seen attending at times. As part of the Safety Patrol at X Middle School, Fillmore and Third solve crimes/mysteries. The series usually presents child-friendly versions of common crimes, such as stolen scooters instead of cars, smuggling tartar sauce instead of drug smuggling, and holding illegal frog races instead of illegal street races.