In Paris far into the future, American Darger and his companion Surplus, an anthropomorphic dog, are living comfortably on credit and high reputations. To improve their financial situation, they hatch a plan. On the invitation of a Madame Mignonette d’Etranger, a rich soon-to-be widow, they reveal that they have found the Eiffel Tower - long gone missing - buried beneath the Seine. Her husband, who is interested in acquiring long-lasting fame before he dies, buys Darger and Surplus’ pitch, excited by the prospect of re-erecting the tower in his name.  Darger and Surplus then need to figure out how to pull the scheme off, as there is a chapbook that reveals the truth - that Darger and Surplus were lying, and the Eiffel tower is not there. However, Darger claims the chapbook has been thrown into the Seine and is gone. That night, Darger hears two intruders talking, but when he opens the door there is only one woman, who gracefully leaps off the balcony to the fire escape. He pursues her as far as he can, but slides down a tiled roof, saved from death only by the gutter. The catlike intruder comes down to him - it is Madame d’Etrnager. She begins to undress him on the roof.  Darger then returns to his apartment, where an astonished Surplus waits. Darger claims he’s fallen in love, and the two begin a steamy affair, but Surplus worries that Madame will find the booking proving the eiffel tower is not under the Seine. Meanwhile, business negotiations continue, and Monsieur is read to go on with the plan. Darger and Surplus have their eyes on the start-up money. But before the deal goes through, Monsieur shows up waving the chapbook, accusing Darger and Surplus of deceiving him. Darger begins to explain himself when Madame walks in, accusing her husband of opposing the affair. She puts on an elaborate act, causing Monsieur to shoot Darger with a smart gun, owned by Surplus. Mignonette jumps in front of him to stop the bullet and falls to the ground. Then, Monsieur kills himself.   The morticians take away Monsieur’s body, but Mignonette has disappeared. Darger becomes depressed, but feels better once Surplus tells him he has struck a deal with the lawyers to pay off their creditors. Before the two depart the city, Darger takes out the chrome pistol and makes it confess, realizing that the pistol was the second intruder in the room with Mignonette, conspiring with her and giving away the information about the chapbook, so Mignonette could be free of her possessive husband. Darger, satisfied by revealing the mystery, walks about with Surplus, abandoning the protesting pistol.