penetrated the majority of
the disguises, "that is--yes, I cannot be mistaken--Ev--Lady Merivale."

His voice dropped slightly as he spoke the name; for he had not expected
that she would accept Miss Penelope's invitation, and was surprised by
her presence.

"Who is the Mephistopheles?" asked his aunt.

Adrien glanced after the couple rather puzzled.

"I don't know," he admitted frankly.

"It is something, a shadow only, like Mr. Vermont," suggested Miss
Penelope.

"It cannot be he," said Adrien, "he is not coming to-night."

Lord Barminster, who had approached in time to hear this speech, looked
affectionately at his son, and Adrien caught the glance and understood
it. But without making any comment, he went in search of his partner for
the next waltz.

Meanwhile, Undine and Mephistopheles had seated themselves in the deep
recess of one of the alcoves.

"May I get you an ice, madam?" asked the Mephistopheles in a queer,
strained voice.

Undine turned her face towards him, and her eyes flashed curiously
through the mask.

"You may," she replied, also disguising her voice, "if you will tell me
who you are."

"That I dare not," was the guarded reply. "My name is never mentioned in
ears polite, you know."

Undine smiled.

"Since you will not tell me your name, perhaps you can tell me mine
without the asking."

"I can, madam. You are--Lady Merivale, who is so fond of the river."

Undine started, her face turning suddenly pale.

"I--what do you mean? Who are you?" she asked, as she peered at him with
straining eyes, seeking to pierce the clever disguise.

"Mephistopheles!" was the calm retort. Then, as if to turn the subject,
he continued lightly: "It is a fair scene, and a fabulous one."

Undine began to have a slight suspicion as to whom her companion might
be, and was far from comfortable in her mind. The hit at the river might
have been only a chance one; but this was doubtful, if Mephistopheles
turned out to be either Mortimer Shelton or Jasper Vermont, as she half
feared.

She strove to conceal her uneasiness.

"The best should be happy and satisfied to-night," she said; "it is a
great success."

"Yes, happy!" agreed the demon, nodding his horned head, "but not
satisfied. That will never be till he sees the marriage of his beloved
son----" He stopped short.

"With Lady Constance Tremaine," finished Lady Merivale, in a low voice,
from which all attempt at disguise had gone.

Mephistoph