The game is designed for three to five players and puts each of them in the shoes of child soldiers during the Warsaw Uprising, serving as members of the Grey Ranks (Polish: Szare Szeregi).

The game itself takes place over the course of ten chapters, each relating to an event that shaped the course of the Warsaw Uprising.

Grey Ranks is a collaborative role-playing game with no GM, and where each player has one scene for their character per chapter.

After the first chapter each player chooses something their character holds dear from their faith, their country, their city, their family, their friends, and their first love - and represents whichever they pick with a tangible symbol that may get destroyed in play.

This means that it gets progressively harder to succeed as the game goes on, modelling the rise and fall of the Warsaw resistance.