There are specific approaches to game design that are not so much a narrative as pretty much scripted. I am thinking of such classics as It came from the Late Late Show (Stellar Games 1989) where you play actors playing roles in a budget pulp horror/sci fi production. Its deliciously satirical and can boarder on the farcical as each player can call a timeout when their actor can throw a tantrum and walk off set in order to get a one off change to sway the outcome of a scene - basically you can successfully argue with the writers in order to change the outcome. In the case of the Late Late Show this is the very reason to play the game but when it comes to more serious games based on a TV series there has to be a tacit agreement between the players and the GM that there is a format and scene progression. Whilst this applies to scenarios in general as opposed to a sandbox approach, specific shows will have a much more formulaic and episodic basis for the context.