Three of the five final episodes in the Hercule Poirot detective series, a longtime favorite on Masterpiece Mystery!, will debut in the U.S. next month as an on-demand series available exclusively through online British content distributor Acorn TV. Masterpiece’s Mystery strand will present the broadcast debut of two detective stories, The Big Four and Deadman’s Folly, July 27 and Aug. 3, respectively. British drama fans who want to catch the series finale will have to sign up for Acorn TV, the subscription-based streaming service specializing in British drama. The distributor will provide the episodes via its website and Roku channel. RLJ Entertainment, which owns Acorn Media Group and Acorn TV, also controls a majority share in Agatha Christie Ltd., the company that manages Christie’s literary works.