When drugstore proprietors Pat Dolan and Budd Doolittle learn that the government has declared a moratorium on the debts of all soldiers, they believe they have finally found a way to keep bill collector Herman Mulligan at bay. Hoping to trick his bumbling partner into enlisting in the Army and avoiding the service himself, Pat puts the store in Budd's name and tries to confuse him at the recruitment office. Pat's plan fails, however, when Budd follows his instructions to the letter and signs Pat's name on the registration form. Before the two realize it, they are sworn into service and shipped off to training camp. En route, Budd and Dan befriend "Smiling" Frank Snark, a smooth-talking fixer who calls himself the "man behind the scenes." Snark sees two easy marks in Budd and Dan and soon has them believing that they will be needing his services to survive in the Army. Dan and Budd also meet Buck Private Wonderful Smith, a befuddled soldier who thinks he is on the wrong train and tries to find his way by calling President Franklin Roosevelt from a train station. Believing that they have escaped from Mulligan and his bully tactics, Budd and Dan arrive at the training camp only to discover that Mulligan has also enlisted, and that he is their unit sergeant. Budd and Dan soon fall into even greater debt in the Army as they succumb to Mulligan and Snark's clever loan tricks. They also get mixed up in the love troubles of fellow soldier Don Lewis, whose parents have vowed to break up his relationship with cabaret singer Gail Nash. While Don's parents are on their way to the camp to stir up trouble, Don is caught A.W.O.L. and is sent to jail. As a favor to Don, Budd and Dan agree to keep Don's parents away from Gail, but they are beaten to the task by Avis, a gold digger who poses as Gail and gets Mr. Lewis drunk. When Dan and Budd discover that Avis has used her wiles to get Mr. Lewis to award her a generous check as a wedding gift, they quickly hide Don's drunken father in a restroom before Mrs. Lewis finds him. At Snark's suggestion, Don and Budd agree to have Mr. Lewis trade his civilian clothes for Snark's uniform, but the switch only lands Mr. Lewis in jail with Budd and Don. Snark helps Mr. Lewis, Budd and Don escape for a two hundred dollar fee, but is later arrested himself when caught in civilian clothes. Mrs. Lewis and Mulligan pursue Don, Budd and Mr. Lewis, and a wild jeep chase ends up back in camp, where the military commandant praises Budd and Don for having successfully tested the Army's new jeeps. The Major then reprimands Mulligan for operating a loan racket on the camp and he is sent to jail.