The clock of Brixton Town Hall was striking the hour of 1 a.m. as Chief Inspector Kerry inserted his key in the lock of the door of his house in Spenser Road.  
A light was burning in the hallway, and from the little dining-room on the left the reflection of a cheerful fire danced upon the white paint of the half-open door. Kerry deposited his hat, cane, and overall upon the rack, and moving very quietly entered the room and turned on the light. A modestly furnished and scrupulously neat apartment was revealed. On the sheepskin rug before the fire a Manx cat was dozing beside a pair of carpet slippers. On the table some kind of cold repast was laid, the viands concealed under china covers. At a large bottle of Guinness's Extra Stout Kerry looked with particular appreciation.
 
He heaved a long sigh of contentment, and opened the bottle of stout. Having poured out a glass of the black and foaming liquid and satisfied an evidently urgent thirst, he explored beneath the covers, and presently was seated before a spread of ham and tongue, tomatoes, and bread and butter.
 
A door opened somewhere upstairs, and:
 
“Is that yoursel', Dan?” inquired a deep but musical female voice.
 
“Sure it is,” replied Kerry; and no one who had heard the high official tones of the imperious Chief Inspector would have supposed that they could be so softened and modulated. “You should have been asleep hours ago, Mary.”
 
“Have ye to go out again?”
 
“I have, bad luck; but don't trouble to come down. I've all I want and more.”
 
“If 'tis a new case I'll come down.”
 
“It's the devil's own case; but you'll get your death of cold.”
 
Sounds of movement in the room above followed, and presently footsteps on the stairs. Mrs. Kerry, enveloped in a woollen dressing-gown, which obviously belonged to the Inspector, came into the room. Upon her Kerry directed a look from which all fierceness had been effaced, and which expressed only an undying admiration. And, indeed, Mary Kerry was in many respects a remarkable character. Half an inch taller than Kerry, she fully merited the compliment designed by that trite apothegm, “a fine woman.” Large-boned but shapely, as she came in with her long dark hair neatly plaited, it seemed to her husband—who had remained her lover—that he saw before him the rosy-cheeked lass whom ten years before he had met and claimed on the chilly shores of Loch Broom. By all her neighbors Mrs. Kerry was looked upon as a proud, reserved person, who had held herself much aloof since her husband had become Chief Inspector; and the reputation enjoyed by Red Kerry was that of an aggressive and uncompanionable man. Now here was a lover's meeting, not lacking the shy, downward glance of dark eyes as steel-blue eyes flashed frank admiration.
 
Kerry, who quarrelled with everybody except the Assistant Commissioner, had only found one cause of quarrel with Mary. He was a devout Roman Catholic, and for five years he had clung with the bull-dog tenacity which was his to the belief that he could convert his wife to the faith of Rome. She remained true to the Scottish Free Church, in whose precepts she had been reared, and at the end of the five years Kerry gave it up and admired her all the more for her Caledonian strength of mind. Many and heated were the debates he had held with worthy Father O'Callaghan respecting the validity of a marriage not solemnized by a priest, but of late years he had grown reconciled to the parting of the ways on Sunday morning; and as the early mass was over before the Scottish service he was regularly to be seen outside a certain Presbyterian chapel waiting for his heretical spouse.
 
He pulled her down on to his knee and kissed her.
 
“It's twelve hours since I saw you,” he said.
 
She rested her arm on the back of the saddle-back chair, and her dark head close beside Kerry's fiery red one.
 
“I kenned ye had a new case on,” she said, “when it grew so late. How long can ye stay?”
 
“An hour. No more. There's a lot to do before the papers come out in the morning. By breakfast time all England, including the murderer, will know I'm in charge of the case. I wish I could muzzle the Press.”
 
“'Tis a murder, then? The Lord gi'e us grace. Ye'll be wishin' to tell me?”
 
“Yes. I'm stumped!”
 
“Ye've time for a rest an' a smoke. Put ye're slippers on.”
 
“I've no time for that, Mary.”
 
She stood up and took the slippers from the hearth.
 
“Put ye're slippers on,” she repeated firmly.
 
Kerry stooped without another word and began to unlace his brogues. Meanwhile from a side-table his wife brought a silver tobacco-box and a stumpy Irish clay. The slippers substituted for his shoes, Kerry lovingly filled the cracked and blackened bowl with strong Irish twist, which he first teased carefully in his palm. The bowl rested almost under his nostrils when he put the pipe in his mouth, and how he contrived to light it without burning his moustache was not readily apparent. He succeeded, however, and soon was puffing clouds of pungent smoke into the air with the utmost contentment.
 
“Now,” said his wife, seating herself upon the arm of the chair, “tell me, Dan.”
 
Thereupon began a procedure identical to that which had characterized the outset of every successful case of the Chief Inspector. He rapidly outlined the complexities of the affair in old Bond Street, and Mary Kerry surveyed the problem with a curious and almost fey detachment of mind, which enabled her to see light where all was darkness to the man on the spot. With the clarity of a trained observer Kerry described the apartments of Kazmah, the exact place where the murdered man had been found, and the construction of the rooms. He gave the essential points from the evidence of the several witnesses, quoting the exact times at which various episodes had taken place. Mary Kerry, looking straightly before her with unseeing eyes, listened in silence until he ceased speaking; then:
 
“There are really but twa rooms,” she said, in a faraway voice, “but the second o' these is parteetioned into three parts?”
 
“That's it.”
 
“A door free the landing opens upon the fairst room, a door free a passage opens upon the second. Where does yon passage lead?”
 
“From the main stair along beside Kazmah's rooms to a small back stair. This back stair goes from top to bottom of the building, from the end of the same hallway as the main stair.”
 
“There is na either way out but by the front door?”
 
“No.”
 
“Then if the evidence o' the Spinker man is above suspeecion, Mrs. Irvin and this Kazmah were still on the premises when ye arrived?”
 
“Exactly. I gathered that much at Vine Street before I went on to Bond Street. The whole block was surrounded five minutes after my arrival, and it still is.”
 
“What ither offices are in this passage?”
 
“None. It's a blank wall on the left, and one door on the right—the one opening into the Kazmah office. There are other premises on the same floor, but they are across the landing.”
 
“What premises?”
 
“A solicitor and a commission agent.”
 
“The floor below?”
 
“It's all occupied by a modiste, Renan.”
 
“The top floor?”
 
“Cubanis Cigarette Company, a servants' and an electrician.”
 
“Nae more?”
 
“No more.”
 
“Where does yon back stair open on the topmaist floor?”
 
“In a corridor similar to that alongside Kazmah's. It has two windows on the right overlooking a narrow roof and the top of the arcade, and on the left is the Cubanis Cigarette Company. The other offices are across the landing.”
 
Mary Kerry stared into space awhile.
 
“Kazmah and Mrs. Irvin could ha' come down to the fairst floor, or gene up to the thaird floor unseen by the Spinker man,” she said dreamily.
 
“But they couldn't have reached the street, my dear!” cried Kerry.
 
“No—they couldn'a ha' gained the street.”
 
She became silent again, her husband watching her expectantly. Then:
 
“If puir Sir Lucien Pyne was killed at a quarter after seven—the time his watch was broken—the native sairvent did no' kill him. Frae the Spinker's evidence the black man went awe' before then,” she said. “Mrs. Irvin?”
 
K............