Not even the owners of the building suspected the remarkable transformation that had taken place within their own property.
What had once been an ordinary office with a small adjoining room had become something altogether different.
The walls disappeared behind a maze of polished wires, gleaming instruments and carefully arranged dials. Every inch of the laboratory reflected countless hours of patient craftsmanship.
Valmon Dain had carried every component upstairs himself.
Piece by piece.
Journey after journey.
Then, with the same unwavering precision that marked all his work, he assembled the apparatus with his own hands until every wire, every switch and every mechanism occupied its exact position.
The laboratory had become far more than a workplace.
It had become an obsession.
No one understood how completely it had taken possession of him.
Not even Dain himself.
The change had been gradual.
Almost invisible.
Yet utterly relentless.
The invention slowly became the centre of his existence.
Old acquaintances saw less and less of him.
His comfortable home in Hendon became little more than a place to sleep whenever necessity demanded.
In truth, Valmon Dain had become a guest in his own house.
Instead, he lived another life.
A quieter life.
A hidden life.
The man known as Mr. Landring Dent of the Kingsway offices gradually became more real to the outside world than Valmon Dain himself.
Such was the strange contradiction of the man.
He was celebrated throughout Britain, yet lived behind a mask.
One identity was admired by the public.
The other was known by no one.
With that contradiction firmly concealed, Valmon guided his powerful motorcar through London's crowded streets.
In his pocket rested the anonymous letter addressed to Scotland Yard.
Even that letter betrayed nothing.
It had been printed rather than written, every upright capital carefully disguising his handwriting.
Only one detail remained personal.
Pressed into the warm sealing wax was the unmistakable impression of his right thumb.
Why he insisted upon leaving it there was a secret known only to himself.
He drove eastward until the busy streets narrowed into the crowded districts surrounding Aldgate.
From there he continued towards Mile End Road before finally stopping outside a small garage.
A bright red pillar box stood only a few yards away.
The mechanic emerged, wiping his hands on a piece of cloth.
"Petrol, sir?"
"Please. Two gallons."
The request was typical of Valmon.
He never asked for "a tank."
He asked for precisely the quantity he required.
While the attendant filled the tank, Valmon produced a pound note from his wallet.
As the mechanic disappeared inside to collect the change, Valmon crossed casually to the pillar box.
With the effortless ease of a man performing a familiar routine, he slipped the sealed letter through the narrow opening.
It vanished into the darkness.
The action lasted no more than a second.
Years later, Valmon Dain would remember that insignificant movement with painful clarity.
For that simple act would become the turning point of his life.
It was the thirty-fourth anonymous warning he had sent to Scotland Yard.
The previous thirty-three had disappeared into silence.
This one would not.
Without knowing it, Valmon had thrown down a challenge.
And this time...
Fate accepted it.