"The Big Door Prize" is a detective science fiction series about a small town where an unexpected "path to truth" opens up. Everything here goes on as usual: housewives drearily go grocery shopping, waiting for their husbands to come home from their dreary jobs, and cashiers drearily ring up cabbage and beans. But suddenly, in the storage room of the local supermarket, a mysterious machine appears, either from the future or from another planet, promising to reveal the true potential of each resident.