"The Lesson" is the twenty-eighth episode of Season 2 of The Amazing World of Gumball. It is the sixty-fourth episode overall.
When Gumball and Darwin cheat on their math test, they get detention from Principal Brown, and have to escape.
The episode begins with Gumball
studying for their math test, but, they get get bored easily, so they start playing, distracting them from studying. The next day, they complain about how they should have studied last night while eating pages off of books to "absorb the information." But then, they realize that they are eating the pages of the wrong book. Since they only have 10 minutes, they both decide to cheat by writing facts on Darwin's face.
Later, they end up in Principal Brown's office, resulting in a Spring break detention. In the detention room, Gumball and Darwin try to talk to each other in secrecy, but, it's revealed that they're actually saying what they were thinking out loud, leading to the duo getting beaten up by the detention "inmates." Gumball and Darwin then decide they must look older in order to get the respect from the detention inmates by drawing fake facial hair with markers, but, it ends up with Gumball getting his face squeezed by the Pink Bear after offending him. The Bomb Guy demands Pink Bear to stop, Gumball then thanks him, and says he owes him one, but the Bomb Guy replies, "You're gonna owe me a lot more than that if you want my protection."
Gumball and Darwin are then seen cleaning Brown's room. When Miss Simian closes the door, Gumball and Darwin then open all the cabinets in Brown's desk, and find the school plans which the Bomb Guy wants Gumball and Darwin to steal. They are then distracted by Brown's calendar, and get caught, resulting them in a trip to the "Correctional Room." The detention song then plays, showing the duo stealing a paper clip, spoons, a rake, and a rope for the Bomb Guy. The song ends with chaos in the detention room, causing Brown to burst in there, giving the Bomb Guy a chance to escape with the stolen items.
The duo follows the Bomb Guy, and ask if they can escape with him, which he refuses. While the Bomb Guy is inside the vent, Gumball jumps on him, causing the vent floor to fall to the side, revealing they are above Brown's office. The Bomb Guy allows them to escape together with him so that Gumball and Darwin can help him up, but, they accidentally awaken Brown, who announces on the speakers that there is a detention break. The 3 escapees goes up to the rooftop inside the vent, but, they find themselves stuck, as the rooftop vent cannot be opened. Gumball then angers the Bomb Guy, causing his fuse to go off without him knowing, and they escape down in time for him to go off and explode the vent. His last words are "Well played."
The duo then figure out the rake and the rope were supposed to be used for a grapple hook, but, it requires math to be used, and they fail, causing the hook to break one of the windows in the school. Brown then arrives to the roof, and Gumball and Darwin attempt to jump off and land on a vehicle, but, they miss, and fall on the cement. They then laugh at Brown saying that they have escaped. The episode ends with Brown saying "I don't know why they are so happy, they still have to come back here tomorrow."
- This episode aired one year after the start of Season 2.
- This is the first time the school's rooftop is shown.
- The students seen in detention have never been seen around Elmore Junior High before.
- Gumball states that they are in the seventh grade, despite Miss Simian having been described as a second grade teacher - this is because the schooling systems in the US differ from the UK (in the UK, second grade of secondary school is equivalent to seventh grade in the US).
- This is the fifth time that Gumball got detention; the first four were "The End," "The Mystery," "The Curse," and "The Meddler."
- This also gets Darwin a second detention with Gumball. The first happened in "The End."
- The ending scene, where Gumball and Darwin jump off the roof rather than get caught by Principal Brown, may be a reference to the ending scene of the film Thelma & Louise, where they also jump from a large height rather be captured by authorities.
- The mathematical theorem that Gumball recites in the beginning is the Pythagorean Theorem.
- Gumball and Darwin act out scenes from several different movies in the beginning.
- Star Wars Episode V: The Empire Strikes Back: After Darwin fails to answer his question, in Darth Vader's voice, he chokes Gumball with the force as he says "You have failed me for the last time..."
- They draw facial hair that looks exactly like Homer Simpson's from The Simpsons.
- When the Pink Bear attacks Gumball, the ink markings drawn on the latter disappear.
- Certain US reruns have this episode rated TV-Y7 rather than TV-Y7-FV.
- When Bomb Guy says "Well played," his one arm is missing. But, when Gumball says "I was learning from the best," both his hands can be seen.
- When Gumball and Darwin try to jump on the car, Darwin's eyebrows disappear.