(FORTUNE Small Business) – It is the entrepreneurial equivalent of the under-dog Red Sox taking on the mighty Yankees: Season Ticket Solutions (STS), a small, Boston-based ticketing company, is suing industry titan Ticketmaster, accusing it of stealing STS technology, which handled the management, tracking, and online reselling of season tickets. According to STS co-founder Tagg Romney (son of Massachusetts Governor Mitt Romney), in fall 2001, Ticketmaster offered to buy STS for $12.5 million and then, during the due-diligence process, scrutinized STS's source code and business plan. Two months later Ticketmaster backed out of the deal without an explanation; a month after that it introduced a nearly identical product of its own. (The company has refused to comment.) In January, STS filed suit against Ticketmaster for at least $12.5 million, including punitive damages of $100 million. FSB's Eilene Zimmerman spoke with Romney about the lawsuit.

Why did you wait three years to sue Ticketmaster? Three of us wanted to close the business and fight from the beginning, but one of the founders still wanted to try to make a go of it, so we agreed to wait. In late 2002 he gave up.

Did you ever doubt Ticketmaster's intentions? They signed a nondisclosure agreement; the guy leading negotiations said Ticketmaster was heart-attack serious about closing the deal and had never signed a term sheet without executing it.

You and the other founders have moved on to other careers, so why bother with a lawsuit? Because we have been cheated, and they were brazen about it. It took us years and millions of dollars to come up with our software. It's the opposite of the entrepreneurial American dream--you work hard, come up with a product people want, are on track for success, and then a big company comes along and squashes you.