The narrative that leads the players through the game and gives them their roles and mission
In terms of design, is the designer being reminded here enough to consider what and how to introduce the Escape Room - enough info to be interesting but people can be put off by a game that is too 'worthy' or 'educational' it has to be fun - hard/challenging/frustrating fun, but fun is also part of the story that the designer has to incorporate. Even a game addressing homelessness, if anything it might be more important that the frustration element gets satisfied. I don't know if that should go here or elsewhere, but the title, the narrative, the story is also in the dosing.