A national retailer purchased the iconic Sullivan’s Steakhouse building at 17795 Dallas Pkwy with plans to add three stories, Bisnow learned first. The buyer is undisclosed, which means there's actually a fourth story—and it's a mystery. (Call Nancy Drew)

McGray Group II sold the building, and the nameless buyer is mum on its plans, says Structure Commercial prez Eric Deuillet, who closed the sale with Lee & Associates principal Nathan Denton. The sale includes a three-story parking garage behind the 11k SF former restaurant. Sullivan’s, which is part of the Del Frisco Restaurant Group, closed in summer 2012. The seller originally bought the site from Del Frisco’s and unsuccessfully tried to lease it before putting it on the chopping block.

Eric (right, with Nathan) tells us high-end restaurants are going to a smaller footprint. After exhausting all the obvious restaurant users locally and nationally, the sales team concluded mammoth restaurants are simply not in vogue. That meant searching for an alternative use. The location along the Tollway, combined with the parking garage, make this an appealing site, he adds. Eric tells us he's getting more listings and adding more brokers. When he can sneak away, he spends time with his wife, Heather, and the kids, 6-year-old Nicholas and 3-year-old Alexandra.