“Your part will be to keep Albert in sight and watch the others.  Doria will probably believe my excuse for going down to Como isn’t true, and he is therefore likely to jump at the opportunity to get on with it.  There’s just a chance of poison.  I don’t like to get Albert across to Poggi, because there he would be much easier to tackle than here.”

“He’s awake to the critical situation?”

“Yes, I’ve made it clear.  He’s promised not to eat or drink anything, except what I bring home with me to-night from here.  Our game is that he’ll be indisposed to-morrow and keep his private rooms.  He’ll pretend that he’s done himself too well with you to-night.  I shall be with him—­I don’t sleep to-night, but play watch-dog.  To-morrow his breakfast will go away untouched—­and mine also.  We shall then partake of the secret food.

“After noon it’s up to you.  I can’t say what Doria will do; but you mustn’t give him the chance to do anything.  If he wants to see Albert, use your authority and tell him he cannot do so until I return.  Put the blame on me; and if he’s wicked use your iron.”

“He may, of course, bolt when he knows the game is up,” said Mark.  “He may be off already.”

“Not he,” answered Peter.  “It’s contrary to reason to suppose he’ll guess that I can possibly know what I know.  He underrates me far too much to give me credit for that.  He won’t beat it; he’ll bluff it—­till too late.  I don’t fear to lose him; I only fear to lose Albert.”

“Trust me that far.”

“I’m going to.  And I want to plan a little surprise of some sort, so that Albert unconsciously helps us.  We can’t ask him to do anything cute himself; he’s not built that way; but he’s the king to be guarded and if the king makes an unexpected move, much may be gained.  We’ve got to be alive to a dozen possibilities.  If, for instance, poison is attempted and found to fail—­”

“How if we gave it out that it had succeeded and that Mr. Redmayne pretended he was mighty ill an hour after breakfast?”

“I’d thought of that.  But the difficulty would be that we shan’t be in a position to say if poison is really used.  No time for chemistry.”

“Try it on the cat.”

Peter considered.

“A double cross is often a very pretty thing,” he admitted, “but I’ve seen too many examples among the police of digging a pit and falling in themselves.  One difficulty is that we don’t want to alarm Albert more than necessary.  At present he only knows that I think him in danger; but he has not the most shadowy idea that members of his own household are implicated.  He won’t know it till I forbid him to touch his breakfast.  Yes; we can certainly try a double cross.  He shall order bread and milk—­we know who will bring it to him.  Then his cat, ‘Grillo,’ shall breakfast upon it.”  Peter turned to Mark.  “That will convince you, my friend.”

But the other shook his head.