Gerald Payne, a psychology professor at Cotchatootamee College, irritates the students with a teaching experiment in which all students are referred to as numbers. Payne's system, which attempts to prevent favoritism, requires much hard work and restricts dating, and so the students decide to ruin Payne by creating a false student. They pool their papers and soon their creation, number 79, has won all the academic awards for the semester. Number 79, whom the students have named Patty Flynn, is to receive an award at a school assembly, and the co-eds, led by Sally Carlyle, are chuckling over their victory when they are overheard by Payne's secretary, Agatha Frost. Agatha, who is known as Frosty, tells the girls that Payne will be fired and they will be expelled if their scheme is revealed, and so Sally calls New York, where fellow student Bingo Brown is picking up orchestrations for the music he composed for the upcoming school show. After Sally tells Bingo to hire someone to play Patty, he approaches would-be singer Betty Reilly. At first Patty refuses his proposal, despite his assertion that she could be discovered by Broadway producer Max Hillman, who will be at the school show. Betty changes her mind, however, when her bumbling brother Eddie and his pal, Nick Cramer, reveal that they "borrowed" a race horse, entered it in a race in her name and are now wanted by the police. Betty goes to the college to hide out and arrives at the assembly just in time to collect the award for Patty Flynn. Payne is astonished by Betty's slang-filled speech, and in order to substantiate the charade, Betty convinces him that overwork due to his experimental system has caused her to have a nervous breakdown. She further convinces him that only relaxing his edicts about dating will prevent the other students from suffering a similar fate. Betty arranges for Payne to escort Sally to an upcoming dance, and after he kisses Sally during a rehearsal for the show, they realize that they are in love. Eddie's arrival ruins everything, however, for when he is picked up by the police, he is taken to Payne, to whom he reveals Betty's true identity. Furious about the deception but wanting to protect the kids, Payne resigns without telling Dean Andrew Wharton about their scheme. Payne then breaks up with Sally and castigates the students for their interference. He also tells them that they must stay in college rather than rush to join the military and fight in the war, for gaining knowledge is serving their country as well. The contrite students confess to Wharton, who agrees to reinstate Payne and expel them. When Wharton forbids them to hold the show, Payne and Frosty conspire to distract him while the kids perform. Wharton hears the music, however, and is about to cancel the show when the kids' final number, "You Got to Study, Buddy," wins the approval of two visiting military officials with its theme of staying in school. Wharton signals his approval, Payne and Sally are reconciled and Betty is a success.