The number is spoken twice, and the two men who speak it are not the same man, though they share a name and a face. In the first minute of “Judgment Night,” before anyone on screen has said a word, Rod Serling’s voice enters the ship into the record the way a clerk would: her name, her registry, her gross tonnage, her age. Five thousand tons. Twenty minutes later, in a small cabin that is not on that ship, Carl Lanser, humming to himself, pleased with the evening’s work, says the figure back. A five-thousand-tonner, he tells the young officer who has knocked at his door; wasn’t that what the registry said? It is the same number and the same word. “Registry” belongs first to the narrator’s log and then to the commander’s kill. Without announcing it, the episode has shown that a single entry can sit in two books at once: the book in which a ship is a ship, with a sailing time and a course and a latitude, and the book in which a ship is a quantity of tonnage credited to the man who removed it from the sea. One number, two ledgers. That is the structure of the whole twenty-five minutes, and it is a better place to begin than the premise everyone remembers, because the premise — an amnesiac on a doomed freighter who turns out to be the doom — is the least interesting fact about how the episode is built.

Consider what the opening narration is, as a piece of language. It is a log entry with an interruption. Serling begins in the register of documentation: registry British, tonnage five thousand, age indeterminate, one day out of Liverpool, destination New York, and then a list of what the log duly holds — sailing time, course, weather, temperature, longitude, latitude. Only after the inventory is complete does the voice turn against its own form and name the thing the log cannot carry, the fear that comes over the deck like fog, that keeps time like the pistons, that breaks every hour into minutes of waiting. The ship has lost her convoy; she is old and blind and alone; she carries, in the narration’s last and most carefully placed word, a premonition of death. The passage is admired for its atmosphere, and it earns that, but its real work is grammatical. It establishes two kinds of time and two kinds of record before a single character appears, and it tells us which kind the episode will be about. Clock time and calendar time go into the log. Duration — the felt length of an hour, the parceling out of minutes — does not. The episode is set in the second kind of time and narrated from the first.

The closing narration completes the frame in the same vocabulary. It returns to the ship’s name and destination, fixes the year, and then produces an image that is not maritime at all but mercantile: the ledger of a life opened and examined, the tally made, the reward or the penalty paid. Paying the fiddler. Comeuppance. Justice meted out. Every noun in the last thirty seconds is a noun of accounting or of measure, and the man being accounted for is given, at the end, his full entry — name, former rank, the navy he served, the state that navy belonged to. The opening is a log and the closing is an audit, and both are spoken by a voice that stands outside the ship and outside the loop, in a place where books can still be opened and closed.

Between those two pieces of bookkeeping the drama is an anxious inventory of records, and the anxiety is not incidental. Jerry Potter, the American from the War Production Board, has been playing a game with the purser’s list, trying to imagine a face for every name, and he found Lanser’s name there and guessed at a face that turned out to be wrong: an old language professor from Oxford. The captain, when he summons Lanser to the bridge, does so with a document in mind; on the passenger manifest, he explains, Lanser’s passport number was not put down. The record has a blank exactly where identity should be. Lanser has no wallet on him and says the passport must be in his cabin, and the captain, being a courteous man on a British ship, tells him to produce it sometime in the next few days — and sends a steward down anyway, because he wants to see it. In the cabin the steward finds not a passport but a cap, a German naval officer’s cap, a submarine commander’s, as the steward with a merchant seaman’s expertise identifies it at once, and inside the cap is the name. The manifest lacks the number; the cap supplies the name; the registry supplies the tonnage; the ledger, at the last, supplies the sentence. Even the roll call Lanser screams through the empty ship near the end — Potter, Miss Stanley, Major Devereaux, Captain, Steward — is a list read aloud, the manifest recited by the man whose place on it was never properly filled in.

It is customary to describe Lanser as a man who does not know who he is. The episode is more exact than that, and the exactness matters. On deck, when Barbara Stanley asks whether what ...