“Oh!” exclaimed Lieutenant Hollyer, as the sudden revelation struck him.

“Some time between eleven o’clock to-night—­about the hour when your sister goes to bed—­and one thirty in the morning—­the time up to which he can rely on the current—­Creake will throw a stone up at the balcony window.  Most of his preparation has long been made; it only remains for him to connect up a short length to the window handle and a longer one at the other end to tap the live wire.  That done, he will wake his wife in the way I have said.  The moment she moves the catch of the window—­and he has carefully filed its parts to ensure perfect contact—­she will be electrocuted as effectually as if she sat in the executioner’s chair in Sing Sing prison.”

“But what are we doing here!” exclaimed Hollyer, starting to his feet, pale and horrified.  “It is past ten now and anything may happen.”

“Quite natural, Mr. Hollyer,” said Carrados reassuringly, “but you need have no anxiety.  Creake is being watched, the house is being watched, and your sister is as safe as if she slept to-night in Windsor Castle.  Be assured that whatever happens he will not be allowed to complete his scheme; but it is desirable to let him implicate himself to the fullest limit.  Your brother-in-law, Mr. Hollyer, is a man with a peculiar capacity for taking pains.”

“He is a damned cold-blooded scoundrel!” exclaimed the young officer fiercely.  “When I think of Millicent five years ago—­”

“Well, for that matter, an enlightened nation has decided that electrocution is the most humane way of removing its superfluous citizens,” suggested Carrados mildly.  “He is certainly an ingenious-minded gentleman.  It is his misfortune that in Mr. Carlyle he was fated to be opposed by an even subtler brain—­”

“No, no!  Really, Max!” protested the embarrassed gentleman.

“Mr. Hollyer will be able to judge for himself when I tell him that it was Mr. Carlyle who first drew attention to the significance of the abandoned kite,” insisted Carrados firmly.  “Then, of course, its object became plain to me—­as indeed to anyone.  For ten minutes, perhaps, a wire must be carried from the overhead line to the chestnut-tree.  Creake has everything in his favour, but it is just within possibility that the driver of an inopportune train might notice the appendage.  What of that?  Why, for more than a week he has seen a derelict kite with its yards of trailing string hanging in the tree.  A very calculating mind, Mr. Hollyer.  It would be interesting to know what line of action Mr. Creake has mapped out for himself afterwards.  I expect he has half-a-dozen artistic little touches up his sleeve.  Possibly he would merely singe his wife’s hair, burn her feet with a red-hot poker, shiver the glass of the French window, and be content with that to let well alone.  You see, lightning is so varied in its effects that whatever he did or did not do would be right.