On a desolate, Midwestern county road, a bound man crawls towards a remote postal box, managing to slide a blood-stained plea-for-help message into the slot before a panicking figure closes in behind him. The note makes its way to the county post office and onto the desk of Jasper, a seasoned and skilled "dead letter" investigator, responsible for investigating lost mail and re...无(🔵)效邮件无效邮(🐑)件无效邮件