Armistice Day had done its best to demonstrate the character of a London November. After a drizzle of rain which had persisted from a reluctant dawn to premature darkness, the temperature dropped suddenly in the evening, and the greasy pavements began to congeal, the slush hardening, and showing bright points of frost under the lamplight.

Chief-Inspector Macdonald, driving back to Scotland Yard after midnight, had felt the cold air developing a nipping quality, and realised that he was in for a jolly journey. He guessed that the sudden drop in temperature would cause a fog, probably a thick fog, considering the sodden state of the still air, and crossing the city from the east was likely to be a tedious business. Cautiously, with ever diminished speed, he nosed the Vauxhall through the wreaths of mist which began to swirl around him, meditating that a car was a snare and a delusion in an English winter. He had driven out to Tarbury in Essex, making inquiries about Jem Bligh, a cheerful rogue who had vanished from his usual haunts after a particularly audacious smash and grab raid. Macdonald had not caught Jem, but he had done some useful work in discovering a concealed motor craft in a creek off the Thames estuary, thereby stopping an illicit cargo from leaving the country.

It was one o’clock when he reached Blackfriars and crept through the fog towards the Embankment, meditating that though the London atmosphere had lost its old “pea soup” speciality in the way of colour and taste, it could yet develop a baffling density as thick as the fog banks of Newfoundland.

The Embankment was a fine exhibition of what London could still do; with his fog lamp tilted towards the kerb, Macdonald could just keep to the roadway. Swirling in dense wraiths, the fog poured off the river, lighted sometimes to an infernal glow by Neon lights, scarlet, Mephistophelian, like a stage fire. Despite the lateness of the hour there was still plenty of traffic on the Embankment.

Armistice night was prolific of dinners and dances, an excuse for a riot of amusement among those who had money to spend. Parliament was sitting again; a conference of international experts was being held (as usual) on tariffs and quotas, and it seemed to Macdonald that merrymakers, legislators and foreign experts must all be trying to make their way along the wide road of the Embankment. Taxis honked, careless of by-laws, an ambulance clanged its bell, huge private cars nosed their helpless heads hither and thither to the accompaniment of Cockney aspersions . . . “ ’ere, yer bloody dreadnought, take yerself off the bleedin’ pavement . . . where’s yer red L, yer blinkin’ bargee . . . cripes, son, it’s the Lord Mayor’s coach givin’ a lift to Mr. Mussolini . . . orl right, girlie, orl right, you go ’ome to ma an’ don’t do it again.”

Under Charing Cross bridge there was a particularly bad jam. Opera cloaks and golden slippers, dominoes and masks, diners-out, down-and-outs, dancers and newspapermen, all jostled round the underground station, pushing, laughing, swearing.

A hundred yards farther on, his car jammed by another one, broadside on, in front of him, Macdonald saw a girl in a vivid green cloak, an ermine collar round her throat, looking round half-laughing, half-frightened. A small ragged figure drew near to her from behind, and a skilful hand jerked a bag from under her arm. With the instinct of the policeman, Macdonald was out of his car in a trice, springing towards the little rat of a man who had snatched the bag. With the sudden reaction of the hunted, the man knew he was pursued, dropped the bag and fled into the enveloping fog. He got away, no detective could follow in that lunatic mist, and Macdonald dashed back to the girl in the green cloak, who was standing with a bewildered look on her face, a few yards nearer the bridge.

“This is yours,” said Macdonald, holding out the bag. “I saw it snatched from you. I should put it under your cloak if I were you.”

“Oh, thanks awfully! How terribly nice of you! I’ve lost my aunt’s car, and it’s not so amusing as it should be. I don’t know my way, and taxis won’t take me.”

“Where did you leave the car, and what make is it?” asked Macdonald.

“A Bentley—a big green thing. It was here a minute ago and I got separated from my aunt trying to cross the road to get into it.”

“There’s a green Bentley by the kerb, twenty yards up,” said Macdonald. “Is your name Moira? There’s some one shouting for you if it is.”

“Oh, you are an angel! Where? Honestly I was a bit shattered. . . .”

“This way. I’m a policeman, so it’s all right,” grinned Macdonald, piloting her through the crowd. “Steady on, it’s slippery.”

It was; the now frozen ground was treacherous under foot, and he gripped her arm and pushed her along to the spot where he had seen the Bentley, where a distracted elderly lady was wailing “Moira, Moira,” and an equally distracted chauffeur was saying:

“She was here, me lady, I saw her—gum! and here she is! O.K., miss, you give us a fright and no mistake!”

“All in the day’s work,” said Macdonald, slipping away from the girl’s cries of thanks, and the older woman’s relieved exclamations. “What price my own car? Ten to one it’s a goner. No, it isn’t. Some one missed a chance. Losh Keeps! What a poem of a night.”

He swung his long legs inside the Vauxhall, reflecting that he had broken one of his own rules for once. He had left his car unlocked, with the ignition key in the slot—a positive gift to any of the hungry men huddled under the bridge, a hundred yards from where he had left it standing. He yawned as he let in the clutch and crawled on again. He had only a few hundred yards to go, otherwise he would have given up this wearisome business of jerking on, yard by cautious yard, through a fog which had now reduced visibility to nil. Even the kerb was not to be seen, and the fog came in through the open windscreen, smoky now, and sulphurous to the taste, mingling with the down-dropping smoke from the railway bridge.

A sturdy figure loomed up against his bonnet, something solid in an apparently empty world. His foot on the brake, Macdonald hailed the uniformed figure with relief.

“Give me a lead across the road, Stokes,” he called. “This is about the qualified limit.”

“You’re right, sir,” said the constable, his electric bull’s-eye lamp held to direct the Chief Inspector across a road which he knew as well as his own bedroom. “You’re just about opposite the gates, but you might as well be on Hampstead Heath for all you can see of ’em. I reckon there’ll be some fine goings on one way and another to-night.”

Macdonald edged through the gates which led to Cannon Row Police Station and turned his car more by instinct than vision into the quadrangle at the back of the Yard buildings. Safely parked between a “Black Maria” and a wireless van, he left the Vauxhall with her radiator covered by the padded “nose-bag,” saying, “and that’s that for to-night. There she is and there she can stay, frost or no frost.”

He ran upstairs and left his report, and then set out to walk home to his flat in the Grosvenor Road. As he stepped out on to the Embankment again, Big Ben chimed two o’clock.