Silent Storm: Sentinels is an expansion pack for the original Silent Storm, released in Russia in 2004. It was released to the rest of Europe later the same year with the original game as Silent Storm: Gold Edition.
The expansion pack features a new storyline taking place after the events of the base game. The gameplay is mostly the same, with the biggest change being that the player now earns money doing missions that must be spent on equipment and recruiting squad members.
The story of the Sentinels follows the squad as they investigate a newly formed terrorist group called Thor's Hammer. While the original game took place during World War II and had campaigns based on both sides of the conflict, Sentinels is set shortly after the end of WWII and the beginnings of the Cold War. Due to this the player can recruit squad members that were only available to the Axis or Allied sides in the original game.