The official Gwent website describes the story of Thronebreaker as a new side of the Witcher universe, claiming:
The story of Thronebreaker takes place in locations within the Witcher universe, many of which players have not seen before. players will navigate the expansion with an all new map system made especially for Gwent, which will lead them through side quests and story battles, both of which are supposed to shake up the game’s rules.
Players will also be expected to use their personal customizable battle camp in order to recruit and develop units, manage resources, and build a massive army to fight for Meve’s kingdom.
Gwent: Thronebreaker is planned for release sometime later this year. Gwent, as it stands, is currently in open beta and available to play for free now.
Stay tuned to GameSkinny for more news and information on Gwent as it develops.