Act One

The lights come up on a collection of strange characters who explain how it all began: a fortune, a chase, a foreign place and a will ("There's Something Funny Going On"). The scene shifts to British shoe salesman, Harry Witherspoon, doing inventory in a dreary shoe shop in East Grinstead. He dreams of changing his life but resigns himself to the fact that his life won't change

Meanwhile, a telegram arrives for Harry at his dog-infested boarding house. His landlady and her boarders decide to have a spot of tea – with plenty of steam to open the envelope before he gets home – but Harry returns just in time to open it for himself ("Mr. Witherspoon's Friday Night"). The telegram informs Harry that his Uncle Anthony, whom he has never met, has died. Harry ends up in the office of a solicitor in London, who tells Harry that this mysterious American uncle has left him six million dollars. His Uncle's will stipulates that, in order to get the money, he must travel to Monte Carlo for a week. His traveling companion will be his Uncle Anthony – embalmed and propped up in a wheelchair! Uncle Anthony holds a mysterious heart-shaped box. Harry must swear to fulfill the terms of the will exactly and follow the instructions his Uncle has left for him on a tape recorder, or the money will go to the Universal Dog Home of Brooklyn.

In Atlantic City, the legally blind Rita LaPorta confesses to her optometrist brother, Vinnie Di Ruzzio, that she accidentally fell for a guy who managed her husband's casino. For him, she embezzled six million in diamonds, hidden in a heart-shaped box. She relates, with escalating drama, how she went to her lover's place one night, without her glasses, and saw a woman leaving. In a jealous and blind rage, she pulled a gun but, instead of shooting the woman, she accidentally shot her lover ("Rita's Confession"). We realize that the man she killed is Uncle Anthony. Rita tells Vinnie that she has blamed the embezzlement on him. They must go to Monte Carlo to get the diamonds back before her husband finds out, or they're both dead.

In the dining car of a train bound for Monte Carlo, Harry desperately tries to make it appear that his traveling companion is alive ("Good to Be Alive"). They meet an Italian rascal named Luigi Gaudi, who introduces Harry and his dead uncle to some ladies and offers to show them the town. Harry notices a young woman who seems to be watching him. Overhead, Rita and Vinnie fly toward Monte Carlo. Harry checks into the Hotel de Paris with Uncle. He starts the tape recorder and hears the week of activities that his Uncle has planned. Harry tries to cheer himself up by taking stock of his good fortune but keeps coming back to the fact that he is on vacation with a dead man ("Lucky").

Harry sets off with his Uncle and sees the young woman whom he had noticed watching him on the train. When he confronts her, he learns that she is Annabel Glick from the Universal Dog Home of Brooklyn. Miss Glick is determined to keep an eye on Harry wherever he goes. One false step in following his Uncle's instructions, and the dogs get all the money ("Dogs versus You"). Arriving at Nice airport, Rita searches the phone directory to find at which hotel Harry is staying. At the same time, the bedraggled Vinnie calls his wife, Alice, telling her that he won't be home for dinner. He tells her that Rita's husband might be trying to kill him, but Alice has no sympathy and hangs up on him ("The Phone Call"). Rita finds Harry's hotel, and the chase is on.

Harry shows his Uncle around Monte Carlo, carefully following the instructions on the tape; they go to casinos, skydiving and deep-sea fishing... all with Annabel Glick in hot pursuit. Rita and Vinnie arrive at the hotel.

Harry and Uncle arrive at the Club Continentale, followed by Annabel ("Monte Carlo"). The emcee introduces Dominique Du Monaco in sequins, feathers and stilettos, who pulls Harry from his seat and seduces him – she is a surprise from his Uncle ("Speaking French"). The whole place joins in singing and dancing... except Annabel. Left alone in the midst of the revelry, prim and lonely Annabel Glick reminds herself how meaningful her work is and why she prefers dogs to humans ("Times Like This"). As Harry and Dominique exit, the emcee reminds everyone that Monte Carlo is a magical place ("Monte Carlo – Reprise").

Harry takes Uncle back to his hotel room, leaves him there and goes out gambling, again followed by Annabel. Simultaneously, Rita and Vinnie show up in Harry's room, looking for the heart-shaped box. She's dressed as a maid and not wearing her glasses. Vinnie goes off to follow Harry. Rita sees Uncle Anthony in the chair and is shocked. She still loves him and approaches him tentatively, trying to explain her actions, asking if bygones can be bygones ("Fancy Meeting You Here"). However, when she gives him a hug, she realizes the truth and screams in horror.

At the casino, Harry's on a winning streak at the Roulette table, thanks to his Uncle's infallible system. Annabel chides him for being so shallow, but Harry is suddenly feeling excellent now that he's winning for the first time in his life ("Act I Finale – Good to Be Alive"). Rita appears behind him and surreptitiously sticks a gun in his ribs.

Act Two

The cast recaps where we are in the story as Vinnie enters to find Rita holding a gun to Harry's ribs ("Something Funny's Going On – Reprise"). Rita wants Harry to get Tony and move towards the door. Vinnie struggles to get the gun. A gunshot rings out. Harry and Annabel run away as Rita screams that her brother has a gun. The croupier grabs Vinnie, and Rita runs off.

Harry tries to get into his room but he's forgotten his key. The elevator bell sounds, and he and Annabel duck behind a laundry cart, throwing a sheet over Uncle Tony. Rita, dressed as a maid, uses a master key to enter Harry's room. A real maid enters, albeit very drunk, and mistakes the sheet-covered Uncle for her pile of laundry. She wheels him off. Vinnie appears and bribes a bellhop into letting him into Harry's room. Harry and Annabel realize that Uncle is gone.

A gunshot then rings out from Harry's room. The door opens, Vinnie runs out, Harry and Annabel escape and Rita emerges with the gun. Harry and Annabel rush around Monte Carlo looking for the corpse, Rita rushes around looking for Harry and the heart-shaped box and Vinnie rushes around looking for Rita ("Him, Them, It, Her"). All of Monte Carlo is involved in the crazy search.

Harry and Annabel return to Harry's room. A nun appears with a leper in a wheelchair – not Uncle Tony. A bellhop enters with an ornery Texan in a wheelchair; again, it's not Uncle Tony. Believing that they have lost everything, Annabel and Harry open some champagne, toast their adventures and consider returning to their old lives. They realize that their time together fighting and aggravating each other has actually been enjoyable ("Nice").

After falling asleep, Harry has a nightmare: a telegram arrives that says he is coming back to his old life. The Landlady, Luigi Gaudi, Annabel, Rita and Vinnie all join in the dream, menacing him, as Uncle Tony rises from his chair and leads a horrific kick line ("Welcome Back, Mr. Witherspoon"). Harry wakes from the dream in his room at the Hotel de Paris, flustered to find Annabel by his side in bed. She demurs because she doesn't want him to think that she's the kind of person who just goes out and has fun. A knock interrupts them. It's the maid with Uncle Tony. Annabel withdraws abruptly, wrapping herself in the sheet and preparing to leave. Harry asks his Uncle for advice on getting her to stay ("A Woman in My Bathroom").

The door swings open; Rita enters, pointing her gun. She demands the heart-shaped box. Annabel tells him not to give the diamonds to her, but Harry does it to keep her from shooting. Rita tells them that she loved Tony and asks why Harry is dragging him around after he is dead. When she takes a good look at him, she realizes that the corpse actually isn't Tony! Rita demands to know where Tony is, or she'll shoot Harry. Harry and Anabel prepare to be shot ("Nice – Reprise"). As Rita takes aim, the door slams again and a mysterious Arab enters, who disarms Rita and removes his headdress to reveal Luigi Gaudi. He admits that he is actually Harry's Uncle Anthony! He explains that the corpse is his friend, Luigi Gaudi, and recites the complicated history of how and why he has come up with this elaborate hoax. Rita accidentally killed Tony's friend, Luigi, who was borrowing his place and having a liaison with a woman; Tony is honoring his friend's last wish by giving him this vacation ("Confession 2 – Reprise"). In the heart-shaped box is the corpse's heart.

Rita recoils from the box in her hands. She wants to know where the diamonds are – Tony has hidden them in the corpse's jacket. Vinnie bursts in with Dominique, both dressed as maids. He is running away with her and demands the heart-shaped box. Rita gladly gives it to him. Triumphant, he and Dominique rush out.

Now reunited, Tony and Rita decide that they could start anew here. They begin to leave, taking the diamonds with them ("Fancy Meeting You Here – Reprise"). Harry stops him, concerned about the fact that this means that the dogs won't get the money. Tony gives Annabel a donation of $10,000, since the dog home was Luigi's favorite charity. Tony also gives Harry $500 and reminds Harry to use Luigi's infallible system for roulette.

Harry and Annabel decide that they should extend their vacation just a little longer... and together ("Finale Act II – Good to Be Alive").