Building of Social Assistance

Shinzo Tanaka, aged 16, enters a “social assistance” building, where the sole purpose is to socialize. Except that, one fine day, an unknown man will appear in front of all the residents of the BSA, and force them to play a game, without explanation or precise aim. All the people in the building will have to play this game, without even knowing its origin, and conflicts and alliances will ensue. Why are humans so unfair? How does society work ?