Dos más uno, dos

In England, childhood friends Elena Carson, a modern girl who likes to wear trousers, and Carlos Bentley, a stuffy archaeologist, fail to recognize one another when Elena crashes into Carlos' car on a winding road. Elena returns to the home of her staid aunt Carolina and then visits family friend Don Eduardo, Carlos' uncle. The two realize that Elena is the recklessly driving "flapper" about whom Carlos spoke, and agree to keep her identity a secret. At a tea, which Carlos and Don Eduardo attend, Elena arrives in an old-fashioned dress and conducts herself like a Victorian lady. Carlos, who prefers "pre-war" women, is immediately won over by her traditional charms. Elena tells him that the girl who crashed into him was her wild cousin Peggy, with whom she is often confused. At a costume ball, Carlos proposes to Elena, and before she can accept, he announces the news to Aunt Carrie and the party. Elena admits to Don Eduardo that she loves Carlos, but states that she wants him to love her for the woman whom she truly is. The two contrive a vacation at Don Eduardo's beach house, where Elena does her best to annoy Carlos by forbidding him to smoke his pipe, insisting on playing croquet daily, and showing up for a swimming lesson in an old-fashioned bathing suit, which prompts the laughter of everyone on the beach. As Carlos' patience wears thin, Elena shows up as "Peggy," looking very fetching as she reads a book about archaeology. At "Peggy's" insistence, Carlos breaks his date to take Elena and Aunt Carrie to an abbey near by, and instead assists her in racing Don Eduardo's boat in the regatta. Carlos and Peggy win the race, and at the yachting club, where Elena receives a trophy, the two meet on the terrace and almost kiss, but Carlos pulls away in horror at his supposed infidelity. Back in England, "Peggy" begins to despair as Carlos will not return her letters nor her phone calls. Elena and Carlos wed, and on their honeymoon cruise, she insists that he sleep in the sitting room. Meanwhile, "Peggy" calls and demands that Carlos visit her in her room, where the two embrace passionately. Carlos returns to Elena's room to confess all and finds Elena in the corridor with Henry, an old beau who recognized her as he walked past her room. When the two flee, Carlos finds a steward and searches for them room by room. Finding Elena and Henry, he throws out the latter and demands an explanation from Elena for her wedding night infidelity. As he admits that he loves her cousin Peggy, Elena's old-fashioned nightie slips to reveal Peggy's negligee, and Carlos realizes the ruse. He calls her Peggy and kisses her, and the steward discovers Elena's old-fashioned nightcap and gown that the happy couple have tossed from their porthole.