This "Sweetheart of a Musical" opens with eight girls complaining about the doldrums---they're just not getting enough telephone calls. The solution is simple announces an advertisement for Susan Answer Phone, a telephone answering service. Before the days of answering machines and high technology, the only choice was to hire a service to answer your phone when you weren't home.

This particular answering service is owned and run by Sue, who employs her cousin Ella to answer the phones. Ella has a deplorable tendency to get involved in customers' lives as she takes and delivers their messages. She even falls in love with one of the customers who she has never even met. In It's A Perfect Relationship Ella describes her feelings for Jeff Moss, this unknowing customer. Now, Jeff is a writer who is having trouble getting to work on his next play, and Ella is determined to help him. Whether you call it curiosity or eavesdropping, one thing's for certain, Ella's busybody personality is entertaining!

A subplot involving Sue and Sandor unravels at the same time. Sue falls in love with Sandor, who runs a company called Titanic Records. Conveniently the record company sets up a branch office in Sue's office space. The record company turns out to be a book-making concern, with an ingenious code which Sandor describes to his assistants in It's A Simple Little System. Unknown to anyone, the police are already monitoring Susansweringphone, suspecting that it's a front for a vice ring. Ella takes on a new identity, goes to Jeff's apartment, and convinces him to rework his new play. In the number Hello, Hello There! she teaches him about friendliness. Jeff invites Ella out for the evening, and a friend teaches her the cha-cha in the sizzling Mu-Cha-Cha dance. Eventually Jeff meets her in Central Park and explains that he has grown to love her. He takes her to a party where Ella sings Drop That Name when she finds herself at a loss for conversation. She doesn't think that she's up to Jeff's social status, and sadly slips away as she sings the great ballad The Party's Over. Jeff still doesn't know who Ella really is.