The show opens on the French Riviera, where Lawrence is a con artist making a very nice living off the lonely wealthy women who vacation there, although he justifies that they are equal partners in deluding themselves (Give Them What They Want). His story is that he is a prince whose kingdom is being threatened by revolutionaries, and he is attempting to find the money to raise an army. One of the women who donates to his cause, a divorcee named Muriel, finds herself wondering the next morning if there isn't more she can to help (What Was a Woman to Do).

Lawrence gets word that another well-known con artist, who goes by the name of "The Jackel", is heading to town. On a return trip from Switzerland, he meets Freddy, who is working his small-time grift on a fellow passenger. Assuming that Freddy is the Jackel, Lawrence convinces him that Beaumont sur Mer is not worth his while and sends him on his way. However, a chance encounter with Muriel shows Freddy that Lawrence is a fraud, and he confronts him at his palatial estate. The splendour of Lawrence's world overwhelms Freddy, who begs him to teach him what he knows so that he too can get some Great Big Stuff. Meanwhile, Lawrence asks Andre to make sure Muriel stays away.

Lawrence's assistant-in-crime, the police chief Andre, is unimpressed with Freddy (Chimp in a Suit), and warns that he could give them all away. When Lawrence attemps to show Freddy how it's done by winning over the rich Jolene, his plan backfires as she becomes convinced they will marry and move back to her home (Oklahoma?). In order to get out of this mess, Freddy poses as Lawrence's younger brother, who manages to repulse Jolene enough to make her leave (All About Ruprecht).

Although they had fun working together, the two men get into an argument about which of them is better at their job. They decide to make a bet - the winner gets to stay as the undisputed champion, and the loser must leave town. The bet? The first to take $50,000 from newly arrived "American Soap Queen", Christine Colgate (Here I Am).

Freddy strikes first, posing as a soldier named Buzz who has lost the use of his legs from a rare psychological condition. His only hope is to get treatment from Dr. Emil Sh�ffhausen in Vienna, but that costs $50,000, which he doesn't have, so the situation looks hopeless. Christine is touched by his story and promises him a happy ending (Nothing is Too Wonderful to be True). She runs to the lobby to send a letter to Dr. Sh�ffhausen. Just then, a porter appears, paging the same doctor. Overjoyed, Christine brings him back to the room and introduces him to Freddy (The Miracle). The doctor turns out to be none other than Lawrence, who has overheard the whole thing.

"Dr. Sh�ffhausen" begins his bizarre treatment of Freddy (R�ffhousin' mit Sh�ffhausen), but to little effect. Andre is kept busy with distracting Muriel from interrupting Lawrence, until she convinces him that the distraction would work better from a more romantic angle (Like Zis/Like Zat). As they spend a romantic evening together, so do Dr. Sch�ffhausen/Lawrence and Christine, in an attempt to enrage Buzz/Freddy so that he will find the will to walk again (The More We Dance).

The treatment appears to be working later that evening, as Buzz/Freddy finds new confidence with Christine's help (Love is my Legs). When Dr. Sch�ffhausen/Lawrence comes to collect his payment, Christine says she almost has it - she's just waiting for some more money from her parents. Confused, Lawrence asks about the "soap queen" fortune, but Christine explains that she just won the trip through a contest sponsored by a soap company, and she is not actually rich. Touched that she would selflessly sacrifice so much for a stranger, Lawrence refuses the payment and helps her to leave town before Freddy can finish his con (Love Sneaks In).

However, Christine has fallen in love with Buzz/Freddy, and sneaks back to the hotel. She offers him the money and herself, which he accepts with only the slightest twinge of conscience (Son of Great Big Stuff). As they move towards their big kiss, Christine accidentally knocks him out.

Christine shows up at Lawrence's door, explaining how Freddy abused her trust and took her money. Lawrence is horrified, and offers her $50,000 of his own money to replace what she's lost. She leaves, but re-appears in moments, saying she can't take his money and returning his briefcase. The doorbell rings again, and this time it's Freddy, in his underwear. He explains that Christine knocked him out, took his wallet and clothes, and left. Lawrence is skeptical until they open the briefcase she just returned...instead of the $50,000, inside are Freddy's clothes and a note signed "The Jackel" (The Reckoning).

Realizing that they've both been conned, the two men call a truce. They reminisce about their chosen profession (Dirty Rotten Number), but are interrupted by the reappearance of "Christine", posing now as a real estate agent for a wealthy Greek playboy. She enlists the help of Lawrence and Freddy, and the three of them decide that it would be much more fun working together (Finale).