Sir Nathaniel was in the library next morning, after breakfast, when Adam came to him carrying a letter.

“Her ladyship doesn’t lose any time.  She has begun work already!”

Sir Nathaniel, who was writing at a table near the window, looked up.

“What is it?” said he.

Adam held out the letter he was carrying.  It was in a blazoned envelope.

“Ha!” said Sir Nathaniel, “from the White Worm!  I expected something of the kind.”

“But,” said Adam, “how could she have known we were here?  She didn’t know last night.”

“I don’t think we need trouble about that, Adam.  There is so much we do not understand.  This is only another mystery.  Suffice it that she does know—perhaps it is all the better and safer for us.”

“How is that?” asked Adam with a puzzled look.

“General process of reasoning, my boy; and the experience of some years in the diplomatic world.  This creature is a monster without heart or consideration for anything or anyone.  She is not nearly so dangerous in the open as when she has the dark to protect her.  Besides, we know, by our own experience of her movements, that for some reason she shuns publicity.  In spite of her vast bulk and abnormal strength, she is afraid to attack openly.  After all, she is only a snake and with a snake’s nature, which is to keep low and squirm, and proceed by stealth and cunning.  She will never attack when she can run away, although she knows well that running away would probably be fatal to her.  What is the letter about?”

Sir Nathaniel’s voice was calm and self-possessed.  When he was engaged in any struggle of wits he was all diplomatist.

“She asks Mimi and me to tea this afternoon at Diana’s Grove, and hopes that you also will favour her.”

Sir Nathaniel smiled.

“Please ask Mrs. Salton to accept for us all.”

“She means some deadly mischief.  Surely—surely it would be wiser not.”

“It is an old trick that we learn early in diplomacy, Adam—to fight on ground of your own choice.  It is true that she suggested the place on this occasion; but by accepting it we make it ours.  Moreover, she will not be able to understand our reason for doing so, and her own bad conscience—if she has any, bad or good—and her own fears and doubts will play our game for us.  No, my dear boy, let us accept, by all means.”

Adam said nothing, but silently held out his hand, which his companion shook: no words were necessary.

When it was getting near tea-time, Mimi asked Sir Nathaniel how they were going.

“We must make a point of going in state.  We want all possible publicity.”  Mimi looked at him inquiringly.  “Certainly, my dear, in the present circumstances publicity is a part of safety.  Do not be surprised if, whilst we are at Diana’s Grove, occasional messages come for you—for all or any of us.”

“I see!” said Mrs. Salton.  “You are taking no chances.”

“None, my dear.  All I have learned at foreign courts, and amongst civilised and uncivilised people, is going to be utilised within the next couple of hours.”

Sir Nathaniel’s voice was full of seriousness, and it brought to Mimi in a convincing way the awful gravity of the occasion.

In due course, they set out in a carriage drawn by a fine pair of horses, who soon devoured the few miles of their journey.  Before they came to the gate, Sir Nathaniel turned to Mimi.

“I have arranged with Adam certain signals which may be necessary if certain eventualities occur.  These need be nothing to do with you directly.  But bear in mind that if I ask you or Adam to do anything, do not lose a second in the doing of it.  We must try to pass off such moments with an appearance of unconcern.  In all probability, nothing requiring such care will occur.  The White Worm will not try force, though she has so much of it to spare.  Whatever she may attempt to-day, of harm to any of us, will be in the way of secret plot.  Some other time she may try force, but—if I am able to judge such a thing—not to-day.  The messengers who may ask for any of us will not be witnesses only, they may help to stave off danger.”  Seeing query in her face, he went on: “Of what kind the danger may be, I know not, and cannot guess.  It will doubtless be some ordinary circumstance; but none the less dangerous on that account.  Here we are at the gate.  Now, be careful in all matters, however small.  To keep your head is half the battle.”

There were a number of men in livery in the hall when they arrived.  The doors of the drawing-room were thrown open, and Lady Arabella came forth and offered them cordial welcome.  This having been got over, Lady Arabella led them into another room where tea was served.

Adam was acutely watchful and suspicious of everything, and saw on the far side of this room a panelled iron door of the same colour and configuration as the outer door of the room where was the well-hole wherein Oolanga had disappeared.  Something in the sight alarmed him, and he quietly stood near the door.  He made no movement, even of his eyes, but he could see that Sir Nathaniel was watching him intently, and, he fancied, with approval.

They all sat near the table spread for tea, Adam still near the door.  Lady Arabella fanned herself, complaining of heat, and told one of the footmen to throw all the outer doors open.

Tea was in progress when Mimi suddenly started up with a look of fright on her face; at the same moment, the men became cognisant of a thick smoke which began to spread through the room—a smoke which made those who experienced it gasp and choke.  The footmen began to edge uneasily towards the inner door.  Denser and denser grew the smoke, and more acrid its smell.  Mimi, towards whom the draught from the open door wafted the smoke, rose up choking, and ran to the inner door, which she threw open to its fullest extent, disclosing on the outside a curtain of thin silk, fixed to the doorposts.  The draught from the open door swayed the thin silk towards her, and in her fright, she tore down the curtain, which enveloped her from head to foot.  Then she ran through the still open door, heedless of the fact that she could not see where she was going.  Adam, followed by Sir Nathaniel, rushed forward and joined her—Adam catching his wife by the arm and holding her tight.  It was well that he did so, for just before her lay the black orifice of the w............