After the “Overture,” eight dejected girls lament the lack of telephone calls in Bells Are Ringing; in replay, a vivid “Advertisement for Susanswerphone” describes the benefits of a telephone answering service. This service is run by Sue, with the assistance of her cousin Ella Peterson. Ella has a deplorable tendency to get involved in the lives of the customers as she takes and delivers their messages. Indeed, she has fallen in love with one of them, Jeff Moss, whom she has never even seen. In “It’s a Perfect Relationship” she describes her feelings. Jeff is a writer who is having trouble getting to work on his next play (“On My Own”) and Ella determines to assist him. In the meantime, Sue has fallen in love with Sandor, the head of Titanic Records, who sets up a branch office in her establishment. Actually, this is a book-making concern with a fiendishly ingenious code which Sandor describes to his assistants (“It’s a Simple Little System”) in which horses, race tracks and bets are cleverly hidden behind composers’ names, opus numbers and quantities of copies ordered by the alleged buyers. Police are already monitoring Susanswerphone, suspecting that it is a front for a vice ring, and Ella has difficulty eluding a policeman who is following her (“Is It a Crime?”).

Nevertheless, she gets to Jeff’s apartment, fires him with enthusiasm, and helps him get started with his new play. She also introduces him to the friendliness of people (“Hello, Hello There!”), and he exalts in his new acquaintance (“I Met a Girl”). As their feelings grow warmer (“Long Before I Knew You”) he invites her out for the evening, and a friend teaches her the cha-cha (“Mu-cha-cha”) in case Jeff should take her dancing. Meeting her in Central Park, he explains how he has grown to love her (“Just In Time”), and takes her to a glittering party, where Ella finds herself at a loss in the conversation (“Drop That Name”). Deciding that she cannot live up to Jeff’s status, she sadly steals away (“The Party’s Over”). Meanwhile, Sue and Sandor plan a trip abroad (“Salzburg”) as he tries to borrow money from her to cover some racing losses.

Two other subscribers whom Ella has befriended meet the despondent Jeff in a nightclub, where the floor show consists of songs written by a musical dentist (“The Midas Touch”), and discover that her good works have helped them all; none of them knows that she works for Susanswerphone. They set off in search of her, and the police close in on the bookies. Just as she has decided to run away (“I’m Goin’ Back”), Ella and Jeff are reunited as the curtain falls on the finale.