Ragged Patsy O'Reilly imagines herself as the descendant of Irish nobility. When her father, an impoverished contractor, invents an ore crusher, the family suddenly becomes wealthy and moves to New York City. Patsy is enrolled in a finishing school, and her parents tour Ireland, where they purchase, at their daughter's request, a coat-of-arms from the bankrupt Lord Windbourne family. After the O'Reillys return to the U.S., they are visited by Lady Windbourne and her son, the Lord, who do not mention that the adopted coat-of-arms is their own. Lord Windbourne becomes engaged to Patsy, but is later revealed as an impostor by the true heir to the Windbourne line, Larry Burke, an English officer. Larry marries Patsy and gives her an authentic ancestral name and coat-of-arms.