"Manhattan" (9 p.m., WGN America): This gripping and provocative new drama series is set in Los Alamos, New Mexico, against the backdrop of the clandestine mission to build the world's first atomic bomb. John Benjamin Hickey ("The Big C") shines as a self-destructive physics professor who is recruited to help lead the Manhattan Project and finds himself living in a world where secrets and lies infiltrate all aspects of everyday life.
"Poirot" (9 p.m., PBS): David Suchet begins his final episodes in the popular "Masterpiece Mystery!" series. Tonight, the master sleuth navigates international intrigues while investigating the shocking death of a Russian chess grandmaster.
"Masters of Sex" (10 p.m., Showtime): The excellent second season continues with an episode that has Virginia (Lizzy Caplan) learning about Masters' (Michael Sheen) troubled childhood during a secret rendezvous at a hotel.
Also on Sunday: