Bon Appétit editor Andrew Knowlton attempts to work 24 hours straight at Katz's Delicatessen in New York City. Katz's Deli, which has been around since 1888, is home to the famous scene from "When Harry Met Sally" and offers the best brisket, pastrami, and corned beef sandwiches in NYC. Can Knowlton survive the hectic ups and downs of the busiest deli in the city that never sleeps?