The Witcher 3: Wild Hunt – Hearts of Stone is the first major expansion for The Witcher 3: Wild Hunt, released in October 2015. It adds a new storyline set in the existing game world, where Geralt is hired to deal with Olgierd von Everec, a nobleman with a mysterious and cursed past. The expansion introduces new characters, quests, enemies, and the Runewords system, which enhances gear with powerful effects. It emphasises narrative depth and moral choices, consistent with the tone of the main game.