ke needed no further urging. Important though the work of finding the
antidote was, Eva's call was more imperative to him. He reassured her as
best he could over the wire, for he had no idea what had really
happened. Zita, as might have been expected, on her return to Brent Rock
had been far too clever to disclose the exact truth that Flint had been
abducted, and that while in her own charge.

When she arrived at Brent Rock she had mounted by the same stairway by
which she and Flint had departed. Entering Flint's room, she had raised
the alarm and had acted her part so well that Eva thought that she had
discovered Flint's absence at the precise moment at which Zita had cried
out and she had come running in answer to her call.

Locke gave Hadwell a brief outline of what had just occurred at Brent
Rock.

"Professor," he pleaded, "for Heaven's sake don't fail me. Try as you
never tried before to find the antidote for this strange combination of
poisons. Telephone me when you have it."

Locke seized his hat, and Hadwell redoubled his efforts to fathom the
toxic secret.

At Brent Rock, in the mean time, everything was in confusion, Eva was
almost distracted, and, to add to her discomfort, Paul took occasion to
call.

In the past few days her distrust of him, for she could call it by no
other name, had grown, and the furtive glances which he exchanged with
Zita, little trouble-maker, were not reassuring. But when Eva's maid,
motioning her aside, told her that she had been a witness to the
departure of Zita and Flint, Eva's suspicions from a vague misgiving
became a stern reality. She longed for Locke's return and protection
from the very man to whom she was engaged.

As Locke left the chemist's he noticed a light runabout across the
street, half hidden in the shadows. But he failed to notice the evil
face of De Luxe Dora peering at him from beneath the rim of a
well-pulled-down hat.

"Huh!" she muttered. "We'll get his number and here's where I go after
it."

Locke hailed a passing taxicab, gave a hurried direction to the
chauffeur, and jumped in. The taxi snorted, cut out open, and jumped
forward as the driver clumsily shifted the worn gears. But out of the
shadows there glided a low-hung runabout with a purling motor that
without effort kept Locke's taxi just in sight without seeming to be
following.

At the time that the emissaries abducted Flint he had been roughly
handled and some of his clothing had been t