Technically this is crossover fiction, with the aid of a little unexplained time travel.
“The cat hair! It is impossible!”
“Now, now, old chap” Hastings intervened. “A good brush down with a stiff clothes brush and all will be pristine again.”
“Indeed Mr. Poirot”, Miss Lemon offered. “I have already removed most of it from your overcoat. I will arrange for your suit to be pressed at the Chinese laundry and they will remove the rest.”
“Bah! I do not understand this affection for cats that so motivates certain English ladies.” Poirot pursed his lips as if something tasted bad.
“Oh, that is just Mrs. Downing. Most people do not extend to sixteen Persian cats, each with their own pillow, Poirot. Most people restrict themselves to one or two.” Hastings offered.
“Well me! I will have none of the things.” Removing one last cat hair from his lapel, Poirot settled at his desk to peruse his mail. Miss Lemon took this as her signal to return to the typewriter while Hastings settled into his accustomed seat, drew out the evening paper he had collected from the doorman, and began to turn the pages. He looked up.
“I say Poirot. I realise this might not be the right moment to raise this, but there has been a murder. At the London annual Cat Fancy in Olympia.”
The Cat Fancy was crowded with cages, owners, visitors and cats. Poirot, minced through the Persian area with every sign of continued disgust.
“Over here, towards the far right of the hall, Mr. Poirot.” The Steward who was escorting him directed. “Mr. Qwilleran—a colonial I am afraid, a newspaperman I believe, although I am told he was also a detective, how ironic—was the exhibitor of two Siamese, one male and one female. We have looked after them over night but we have had no luck finding a family member to come and take care of them. Initial enquiries to those who called him an acquaintance, suggest that he may have left the cats, with a sum of money for their care, to the Siamese Cat Society with the hope that the Society would rehome them in any eventuality. Of course… he could not have expected such a one as this.” The man looked pained.
Finding himself standing in front of the cage Poirot gazed at the two cats who sat, curled up in each other in cage, their blue eyes—one pair forget-me-not, the other sapphire—gazing at him with deep thoughts. After a moment or two Hastings, standing behind him, coughed.
“Ah, yes. The cats.” Poirot noted. “They are very distinguished.” He paused. “May I greet them?” Receiving a nod from the steward Poirot removed a glove from his right hand and gently inserted one finger. The darker of the two cats—the label called her seal point and named her Yum Yum —pushed a nose at him. He stroked it. The lighter cat, Kao K’o Kung—chocolate point his label said, his dark mask stark against the cream coat—rolled on to his back and demonstrated the zipper like marks down his belly. Poirot touched it gently, and heard the motor like purr. He reached up a velvet clad paw and placed it in Poirot's hand.
The case, it proved much too easy. Poirot left Japp tying up the loose ends and arresting the lady three cages down who had decided in advance that Mr. Qwilleran was much too strong a challenger to her role of secretary of the local Siamese club; such things, Japp had said, being second only to the Great Hedge Wars as causes for murder in English provincial life.
As they got into the car, Hastings looked down at the large cage Poirot was now carrying. Its contents looked back at him. One of them yawned, her deep pink throat a sharp contrast to her dark fur and Sapphire eyes.
“It is only temporary, mon ami.” Poirot declared. “I am told the Society will shortly find a new home for them.”
“Yes of course, Poirot.” Hastings responded. Poirot was not looking. He was too busy ensuring that the cage went smoothly into the taxi with as little jolting as possible. As Hastings had the worst poker face at his club, and knew it, this was perhaps a good thing.
The next morning Hastings arrived in time for his customary second breakfast (kippers at his club, toast and conserve with Poirot). As Miss Lemon let him in, she placed her fingers over her lips and drew him to a crack in the living room door. There sat Poirot, his napkin around his neck, his toast cut in nine squares, each with their blob of conserve. Each cat sat on a chair drawn up to the table, its black face and bib and black paws rendering it peculiarly formal. Poirot was spreading pate onto a second piece of toast and as Hastings watched, he carefully cut it into even smaller squares before delicately passing them, and watching it be delicately received, one at a time and strictly in turn, to each cat.
“Well, mes amie” Poirot addressed the cats with his customary courtesy, “And which of the cases that have been drawn to our attention shall we consider today?”
Hastings and Miss Lemon could not see their eyes, but watched as Kao K’o Kung lifted his dark gloved paw and tapped one of three letters Poirot had laid out in front of him.
“Somehow, Miss Lemon, I think that the Society will not have to look very far for a new home for these two.”
“Indeed, Mr. Hastings. And I have added a nice new stiff clothes brush to the hallway furniture.