A lady cardsharp tries to con an eccentric scientist only to fall for him.

After Charles Poncefort Pike, an ophiologist and heir to the Pike's Pale Ale fortune, leaves a zoological expedition in the South American jungle, he boards an ocean liner headed for the East Coast. Although the eligible bachelor only has eyes for his book on snakes and is oblivious to all the young female passengers, Jean Harrington succeeds in getting his attention by tripping him as he leaves the dining room. Jean, a con artist and cardsharp who works with her father, ensnares Charlie with her feminine wiles, and despite the warnings of Charlie's suspicious guardian, Muggsy, Charlie falls in love with Jean. Much to her own surprise, Jean also falls in love with Charlie, and informs her father that she intends to go straight. "Colonel" Harrington does not share her good intentions, however, and despite Jean's intervention in his card game that night, Harrington wins $32,000 from the luckless Charlie. Harrington pretends to rip the check up to impress Jean, but Charlie breaks off his engagement to Jean when he learns that she and her father are well-documented con artists. Hurt, Jean's tender thoughts of love turn to calculating thoughts of revenge, and is happy when Harrington produces the check intact. The ship docks, and some time later, the Harringtons encounter their friend Pearly at an East Coast horse race. Pearly, also a con artist, is posing as Sir Alfred McGlennan Keith while living in the Pike hometown of Bridgefield, Connecticut. Still bent on revenge, Jean arranges to pose as Pearly's niece, Lady Eve Sidwich of England. The Pikes throw a lavish introduction party for Lady Eve, at which a clumsy Charlie is astonished by her resemblance to Jean. Although Muggsy insists that Lady Eve and Jean are the same person, Charlie, using backward logic, thinks the resemblance is too close and that consequently, they must be different women. He soon falls deeply in love with Lady Eve. Jean and Charlie become engaged, much to the Pikes's delight, and she continues her pose through their wedding. She finally exacts her revenge on their wedding night by relating a fictional history of love affairs to her stunned husband. Mortified by his new wife's apparently sordid past, Charlie immediately gets off their honeymoon train in his pajamas and later sues for divorce. Now remorseful, Jean realizes that she is still in love with Charlie and insists on settling without renumeration if Charlie will only speak with her, but he refuses. Out of desperation, Jean books passage on the same ocean liner on which Charlie is traveling and again trips him to get his attention. Charlie is thrilled to see Jean, still unaware that she is also Lady Eve, and when he tries to explain that he is married, she assures him that she, too, is married. Muggsy, reacting to the reunion, mutters "Positively the same dame."