Francis Mosses is the new doorman at Apartment 61, working for the Doppelganger Detection Department (D.D.D.). He's responsible for protecting residents and identifying threats. He's become familiar with the schedules of many neighbors, but one remains a mystery: the milkman. His schedule is erratic and seemingly impossible to predict, causing Francis considerable anxiety. The milkman's cap, always worn, reads "Milkman." Francis is disturbed when he sees the milkman covered in blood, questioning if it's a doppelganger or something more sinister.