From the first page of the PDF:
New Sharandar is on the brink of war, with skirmishes already taking place. Heroes are needed to prevent the outbreak of a full-scale war. Can you root out the infernal influence that is the cause of this region’s troubles before it is too late? A Living Forgotten Realms adventure set in Neverwinter for characters of the Heroic tier (levels 1-10).
This adventure is the conclusion of the Devil’s Play Major Quest, which started with NEVE4-1 Hound’s Baying and continued in NEVE4-2 Serpent's Kiss. We recommend that you play the trilogy in order with the same character.