The Last Ship season four premiere on TNT with a two-hour episode Sunday, August 20 Following a series-changing season three finale last year, The Last Ship season four has officially locked its premiere. Look for a two-hour return to the show’s post-apocalyptic world to debut Sunday, August 20 at 9:00pm ET/PT across TNT platforms. RELATED: Daveed Diggs to Star in TNT’s Snowpiercer Series Starring Eric Dane, Adam Baldwin and Bridget Regan, The Last Ship is based on William Brinkley’s popular novel, the series chronicles the aftermath of a global catastrophe that nearly decimates the world’s population.