Richard O’Dwyer, an enterprising 24-year-old college student from northern England, has found himself in the middle of a fierce battle between two of America’s great exports: Hollywood and the Internet.

At issue is a Web site he started that helped visitors find American movies and television shows online. Although the site did not serve up pirated content, American authorities say it provided links to sites that did. The Obama administration is seeking to extradite Mr. O’Dwyer from Britain on criminal charges of copyright infringement. The possible punishment: 10 years in a United States prison.

The case is the government’s most far-reaching effort so far to crack down on foreigners suspected of breaking American laws. It is unusual because it goes after a middleman, who the authorities say made a fair amount of money by pointing people to pirated content. Mr. O’Dwyer’s backers say the prosecution goes too far, squelching his free-speech right to publish links to other Web sites.

Mr. O’Dwyer did not respond to requests for an interview, but his mother, Julia, a nurse with the state-run health service, described him as a somewhat reserved young man who grew up playing Super Mario games on his computer and became devoted to coding. He studies interactive media and animation at Sheffield Hallam University and, his mother said, long ago spent the money he had made from his Web site.