The first showing of "Clone Cadets" marks the beginning of Season Three for the Star Wars: The Clone Wars animated show. It was initially broadcast on September 17, 2010 together with "ARC Troopers" during the season's initial hour-long event. It happens before the events of the first season episode "Rookies." In the timeline of the series, it occurs after the events of the pilot movie Star Wars: The Clone Wars and before the events of the episode "Supply Lines."
On Kamino, five stubborn clone cadets are having a hard time finishing their training. These cadets – Hevy, Cutup, Droidbait, Fives, and Echo – don't seem to work well together, appearing to be a "bad batch". While Shaak Ti and drill instructors Bric and El-Les discuss what to do with the cadets, the clones start to cooperate and embrace their future as soldiers.
Domino Squad is participating in a final exercise on Kamino before they graduate and go to the war. The goal of the exercise is to get to the top of a citadel guarded by training droids. However, the five clones on the squad don't work well as a team, as noted by their instructor, the bounty hunter Bric, who is observing the exercise with his fellow hunter El-Les and Jedi Master Shaak Ti. Bric believes the squad is a lost cause and wants to send these "rejects" to maintenance duty with 99, a clone with deformities.
Bric's assumptions quickly prove to be correct when the practice droids defeat Domino Squad while they are arguing about the proper procedure. As the clones head back to the barracks, Echo reminds his squadmates that they need to follow orders. This leads to a fight between him and CT-782, also known as Hevy, before Bric intervenes and expresses his disappointment. Elsewhere in Tipoca City, Lama Su is thinking about rejecting Domino Squad but decides to let Shaak Ti make the decision because she is in charge of training.
The following day, ARC trooper Commander Colt and two others arrive to oversee the graduation tests. Bravo Squad, the first squad to take the test, passes easily and quickly. When it's Domino Squad's turn, they fail when Droidbait is shot, and Hevy decides to leave him behind. Colt scolds the squad for its mistakes. As they are walking through the barracks, El-Les tells Bric that Domino Squad should get another chance, but Bric doesn't have much confidence in his squad. 99 overhears their conversation.
That night, Fives and Echo ask Shaak Ti to transfer them to Bravo Squad. However, Shaak Ti refuses and explains that they need to learn how to cooperate with their squadmates. She allows them to retake the test the next day. Meanwhile, CT-4040 is called in by Bric for a scolding. The bounty hunter tries to get the clone to attack him, hoping to get him and his squad expelled, but the cadet refuses to give in. The only thing Bric accomplishes is unintentionally giving 4040 a nickname: Cutup.
Later that night, 99 finds 782 trying to desert. He convinces 782, whom he calls Hevy, about the importance of brotherhood and teamwork. The next day, Hevy has taken 99's advice and nickname to heart and takes charge of his squad. This time, the clones have found the team cohesion they were missing before, but when they reach the citadel, they discover that their ascension cables needed to climb it are missing. Bric had stolen them to test their abilities and, if possible, see them fail. El-Les argues that this is unfair to Shaak Ti, but she calmly responds that the Separatists would not fight fairly either.
Domino Squad quickly adjusts to the situation by destroying the wall-mounted turrets and using them as ladders to successfully complete the test. Shaak Ti praises Bric for his efforts in making these clones the best they can be, and Bric has to admit that El-Les was right. Afterward, the bounty hunters give Domino Squad medals for graduating, but as a token of appreciation, Hevy gives his medal to 99 so that he will have a reason to return to Kamino. Domino Squad then joins the other clones as they are sent to the front lines.
While preparing the final test for the cadets, Commander Colt instructs El-Les to set the challenge to "version THX variable 1138." This is a reference to George Lucas' first film THX 1138, and one of many references to it in his work.