'I just don't think our war aims - whatever they may be - and we don't know - justify this level of slaughter.' The poets and soldiers Siegfried Sassoon and Wilfred Owen are dispatched to Craiglockhart War Hospital in Scotland in 1917. There, army psychiatrist William Rivers is treating brutalised, shell-shocked men. It is Rivers' job to fix these men and make them ready to fight again. As a witness to the traumas they have endured, can he in all conscience send them back to the horrors of the trenches?