Susan Miller (Gene Tierney) works behind the girdle counter in a department store and dreams about the beautiful clothes and glamour she can never hope to have. Enter May Worthington (Spring Byington) and Warren (Laird Cregar), a pair of con artists who pose as the mother and uncle of a pretty girl in order to separate millionaires from their money. They convince Susan she has an opportunity to fulfill all her dreams, and the trio heads for Palm Beach. Susan meets John Wheeler (Henry Fonda) who says he is shopping for a sailboat. Believing that he is a millionaire, Warren and May sell him a boat that doesn't belong to them, and make off with his $15,000 life savings. Looking for greener pastures, they work themselves into the family of wealthy Tod Wheeler (John Shepperd), who falls for Sue, posing as "Linda Worthington". But John shows up as a guest of Fenwick and he tells "Linda", not knowing she was part of the scam, that he has a detective after the fake captain (Warren) that sold him the boat. John admits that he is not a millionaire but only a $50-a-week clerk. He asks her to marry him and, over the protests of May, she accepts. Tod, who has been away, wires Linda a marriage proposal which is intercepted by Warren, who accepts on her behalf via a return wire. He intends to blackmail her into marrying Tod and then blackmail the Fenwicks into dissolving the marriage. To get John's money back to him, which she has but can't tell him, Linda enlists the aid of Colonel Prentiss (Henry Stephenson) who runs a gambling house, and the machines are fixed so that John wins his money back. Linda and John go to the terminal to leave, but Tod shows up and she tries to keep him away from John, who knows her as Sue.

Lingerie salesclerk Susan Miller longs for a luxurious life full of interesting people. Susie's opportunity comes in the form of Mrs. Maybelle Worthington and Warren, two swindlers who use pretty girls as decoys to bilk weathly men. As their latest girl has gotten married, Maybelle and Warren need a replacement, and convince the reluctant Susie that all she has to do is be "beautiful but unobtainable." The trio soon establish themselves with Susie posing as Linda Worthington, Maybelle's daughter. They live off rich men who become attracted to Susie, until one day, on Santa Catalina Island, they meet John Wheeler, whom they mistake for a millionaire because he is trying to buy a yacht. Susie and Maybelle pretend to be interested in a particular boat, which they allow John to buy instead. Unknown to John, the man he buys the boat from is not the real owner, Harvey Beasley, but Warren. John does not realize that Maybelle and Susie, of whom he is genuinely fond, are involved in the swindle, and promises them that he will catch the culprits. Sometime later, Susie, Maybelle and Warren take up residence in Connecticut at the home of wealthy Tod Fenwick and his parents. Tod is in love with Susie, and Maybelle and Warren plan on making a million dollars from their marriage. They are surprised by the appearance of John, who is an accountant, and is there to discuss business with Tod. When Susie tries to distract John until his train leaves, she learns that he makes only sixty-five dollars a week and had saved for fifteen years for the $15,000 to buy the yacht. John has big dreams and his ambitions thrill Susie, who finds that she returns his affections. They decide to marry, and despite Maybelle's warnings that she cannot quit so easily, Susie leaves with John. She moves into John's New York boardinghouse, and the young couple plan their future. Wanting to return John's money without him knowing, Susie gives $15,000 to a casino owner friend, Colonel Prentiss, who arranges for John to win the money while gambling. John and Susie decide to go to California to buy a boat, but while they are in the airport awaiting their flight, Susie runs into Tod. Also present are Maybelle and Warren, who have accepted Tod's marriage proposal on her behalf. Susie excuses herself from John, who returns to the casino to gamble again until their flight leaves. Warren tells the colonel that the money Susie gave him was actually his, and threatens to reveal old secrets unless he arranges for John to lose it all. Desperate for John to have his boat, Susie agrees to jilt him and marry Tod if Warren will allow him to keep the money. John, who has been losing, is allowed to win back the $15,000 and returns to the airport, where a goodbye note from Susie awaits him. Just then, however, Kellogg, the private detective hired by John to find the swindler who sold him the boat, arrives and tells John that he has found the culprits. After Kellogg reveals how Maybelle and Warren have been using Susie, John returns to the casino to rescue her. As Kellogg is taking Maybelle and Warren off to be arrested, John assures Susie that he still loves her and believes her to be innocent. The young couple then go off to catch the next flight to California.