Battalion D takes place in the Middle Ages around a team of reject knights who are never given any meaningful tasks or duties. The team consists of their “captain”, Captain Mack, the miniature joker, Jim, the plus-sized knight, Bob, and Zeke, who struggles with his armour.​

After being passed up for any task or duty, Captain Mack complains about his team, pointing out their flaws whilst being oblivious to his own. Suddenly, when smoke bellows out of the castle grounds, Captain Mack sees this as a chance for his team to become the heroes of the kingdom. With a short rally speech, he inspires the team and leads them in a heroic charge towards the castle. Will they become the heroes of their kingdom? (most likely not.)