The tabby eyed the tall man from the shadows. An unusual selection for a companion, but the tabby knew a kindred spirit, and furthermore he smelled of fish. The very fresh-off-the-wharf fish he had been spoiled with as a kitten, when he had been ignorant to London chills and the bristly feel of rat fur on his tongue. This man, despite his fishy smell, was not a cuddly man, hard to charm. But it could be done; Tabby could charm anyone.
Tabby padded silently out of his alleyway after the man. His nose twitched with the familiar smell of pipe tobacco. He followed for a time before the human turned. He allowed him to observe him, and he observed back.
"Stray, I presume," he said. Tabby swished his tail.
"Very well," he said, and began to walk again.
Tabby followed him at a lofty distance for a while, slowly working up to being almost beside him. The human made no objection.
When the human turned his key in his residence's lock, Tabby twined over his legs and inside. The man smiled. "Persistance is a quality I admire, cat," he said.
He allowed Tabby into the sitting room. The cat spotted a bearskin rug before the fire and curled up. Holmes sat amongst his papers and worked, and Tabby dozed.
They shared the fish purchased at the wharf.
Prompt: "A stray comes to visit Holmes..." from Rocktzar, December 11th. This cat may became canonical for me. I dig him.