Counter Truancy Unit (or shortly CTU) is a weapon used by Springfield Elementary School to fight misbehavior of the students. Its headquarters is placed under the school. It is full of computers and big screens that are showing everything what is going on at school. The agents also can get on every camera in Springfield.
Seymour Skinner founded the CTU and engaged some students there. After Lisa had noticed that Jimbo, Dolph and Kearney were playing truant, a field agent Milhouse was sent to spy them, however the bullies soon noticed him.
Later, the CTU enlisted Bart who was sent as a field agent to spy the bullies. Bart tracked them down and learned that they are planning to make a stink bomb and set it off at the school bake sale. However, he was then knocked out by Martin Prince who was a double agent as the bullies had stolen his ant farm.
Bart woke up tied up in the ventilation room where also the bomb with he three-minute timer was. Eventually he got out and Lisa managed to defuse the bomb before it blows.
- Seymour Skinner, leader and operator
- Lisa Simpson, head hall monitor
- Martin Prince, analyst (double agent)
- Database, analyst
- Bart Simpson, field agent
- Cosine, analyst
- Milhouse Van Houten, field agent
- Sherri, field agent (possibly deceased)
- Terri, field agent (possibly deceased)
- Wendell Borton, field agent (possibly deceased)