On the planet Kamino, Jedi General Shaak Ti oversees the training of clone cadets with the help of contracted bounty hunters Bric and El-Les. Bred to be perfect soldiers, the clone cadets must first be subjected to intense physical and mental training before heading off to war.

Battle droids are used at the training facility on Kamino to give cadets a realistic sense of the kind of enemy fire they may encounter on the battlefield.

The Domino Squad includes Hevy, Cutup, Droidbait, Fives and Echo. The squad is told to take the tower in the "Citadel" exercise. Echo, as his nickname suggests, repeats the command to the entire squad, annoying his fellow clones.

Eager to complete the test mission, Hevy breaks formation and tells the others to follow his lead. His squadmates argue if they should follow him.

The constant bickering among Hevy, Cutup, Droidbait, Fives and Echo make them distracted and easy targets for the battle droids. Their inability to work as a team does not go unnoticed by Jedi Master Shaak Ti and the bounty hunter drill instructors who are watching from the observation deck.

Jedi Master Shaak Ti, who is overseeing clone training, notices that Domino Squad is having more difficulty completing their mission than the other clone squads. She believes, along with drill instructor Bric, that these particular cadets are far from ready.

Malformed maintenance duty clone 99 cleans up the mess in the training room that the Domino Squad leaves behind. Even in his simple duties, Clone 99 always has a positive outlook and tries to encourage Domino Squad.

Back in the clone barracks, Echo reminds the rest of the squad that they must follow orders in order to pass their test. The squad members argue once again about who on the team is the weakest link and who should be the leader. The discussion gets tense, and Hevy and Echo begin to scuffle.

Their disappointed drill instructor Bric breaks up the fight, reminding the squad that if they focused on fighting droids as much as they do fighting each other they might stand a chance. Bric reminds the squad that they are almost at the end of their training and they haven't advanced nearly enough.

Bric addresses the clone cadets that in order to be the best of the best -- ARC troopers -- they must pass their training tests first. He introduces them to ARC trooper Commander Colt and others from the Rancor Battalion who will be supervising their graduation tests. Colt reminds the cadets that even though sometimes troops may quarrel, no matter what they are united. Rule 1 is that they must fight together.

ARC Commander Colt watches the clone tests alongside drill instructors El-Les and Bric. He tells El-Les to run the citadel test 11 variation 38. Bravo Squad is up first and performs well, much to the awe of misfit Domino Squad.

Up next is Domino Squad! Echo reminds them all they have to do is follow orders to succeed. As Domino Squad enters the training arena, the passing Bravo Squad jokes that it's "time to watch the Dominos fall." Even the cadets of Domino Squad are questioning themselves.

In the beginning of the exercise, Domino Squad gets closer to the citadel than previously, impressing El-Les. However, Commander Colt thinks their tactics are sloppy. Before long, Domino again fails due to an inability to work together. Commander Colt reprimands the squad for their mistakes, which include breaking formation, disobeying orders, and leaving a man behind. They broke Rule 1 -- they must fight together.

The squad earns an automatic failure for their behavior during their test. In the barracks, Clone 99 overhears El-Les and Bric discussing Domino Squad. El-Les thinks they should take the test again, but Bric thinks Domino Squad is a lost cause and should be transferred to maintenance.

Fives and Echo visit Shaak Ti to request a transfer out of their squad to another. As a Jedi, Shaak Ti believes that the individual and the group are one in the same, much like the clones. She tells the cadets that they are looking out for themselves as individuals, not as a group. Shaak advises them to solve their problems as a whole. She allows Domino Squad to take the test again.

While the rest of the clone cadets are fast asleep in their bunks, Hevy attempts to go AWOL. Clone 99 catches him leaving and tells him that he can't leave his squad in their time of need. Hevy calls his squad a bunch of failures, like 99. 99 reminds him that he can't be called a failure because he never got a chance, unlike Domino Squad.

The next day, the Domino Squad is ready for battle, and ready to finally work as a cohesive team. They all know what they have to do.

With each shot at a battle droid, Domino Squad has each others' backs. Compliments and encouragement have replaced dissent and arguing.

When the Domino Squad reaches the citadel, they discover that their ascension cables needed to scale the wall are missing. Hevy spots the wall-mounted turrets on the citadel wall and comes up with a plan for the squad to use them to climb up to the next level.

Members of Domino Squad climb the disabled turrets like stepladders to the next level of the citadel. Both Bric and El-Les are impressed by the creative problem solving demonstrated by the squad. The cadets have worked together as a unit -- they complete the task and pass their test.

Domino Squad stands at attention while El-Les congratulates them and awards them graduation medals. Finally having graduated, Hevy tells 99 that he was right. When they exchange good-byes, Hevy gives 99 his graduation medal out of thanks for his advice and brotherhood.