When the priest recounted to the lawyer his little interview with old Musgrave in the village, the lawyer was both puzzled and interested. "Why has the Captain bolted?" he asked. "Who are the other people who want him? Who on earth are the Grunovs?"
"For the first, I don't know," replied Father Brown. "Possibly his mysterious sin has come to light. I should rather guess that the other people are blackmailing him about it. For the third, I think I do know. That horrible fat woman with yellow hair is called Madame Grunov, and that little man passes as her husband."
The next day Father Brown came in rather wearily, and threw down his black bundle of an umbrella with the air of a pilgrim laying down his staff. He had an air of some depression. But it was as it was so often in his criminal investigations. It was not the depression of failure, but the depression of success.
"It's rather a shock," he said in a dull voice; "but I ought to have guessed it. I ought to have guessed it when I first went in and saw the thing standing there."
"When you saw what?" asked Granby impatiently.
"When I saw there was only one suit of armour," answered Father Brown. There was a silence during which the lawyer only stared at his friend, and then the friend resumed.
"Only the other day I was just going to tell my niece that there are two types of men who can laugh when they are alone. One might almost say the man who does it is either very good or very bad. You see, he is either confiding the joke to God or confiding it to the Devil. But anyhow he has an inner life. Well, there really is a kind of man who confides the joke to the Devil. He does not mind if nobody sees the joke; if nobody can safely be allowed even to know the joke. The joke is enough in itself, if it is sufficiently sinister and malignant."
"But what are you talking about?" demanded Granby. "_Whom_ are you talking about? Which of them, I mean? _Who_ is this person who is having a sinister joke with his Satanic Majesty?"
Father Brown looked across at him with a ghastly smile.
"Ah," he said, "that's the joke."
There was another silence, but this time the silence seemed to be rather full and oppressive than merely empty; it seemed to settle down on them like the twilight that was gradually turning from dusk to dark. Father Brown went on speaking in a level voice, sitting stolidly with his elbows on the table.
"I've been locking up the Musgrave family," he said. "They are vigorous and long-lived stock, and even in the ordinary way I should think you would wait a good time for your money."
"We're quite prepared for that," answered the solicitor; "but anyhow it can't last indefinitely. The old man is nearly eighty, though he still walks about, and the people at the inn here laugh and say they don't believe he will ever die."
Father Brown jumped up with one of his rare but rapid movements, but remained with his hands on the table, leaning forward and looking his friend in the face.
"That's it," he cried in a low but excited voice. "That's the only problem. That's the only real difficulty. How will he die? How on earth is he to die?"
"What on earth do you mean?" asked Granby.
"I mean," came the voice of the priest out of the darkening room, "that I know the crime that James Musgrave committed."
His tones had such a chill in them that Granby could hardly repress a shiver; he murmured a further question.
"It was really the worst crime in the world," said Father Brown. "At least, many communities and civilizations have accounted it so. It was always from the earliest times marked out in tribe and village for tremendous punishment. But anyhow, I know now what young Musgrave really did and why he did it."
"And what did he do?" asked the lawyer.
"He killed his father," answered the priest.
The lawyer in his turn rose from his seat and gazed across the table with wrinkled brows.
"But his father is at the castle," he cried in sharp tones.
"His father is in the moat," said the priest, "and I was a fool not to have known it from the first when something bothered me about that suit of armour. Don't you remember the look of that room? How very carefully it was arranged and decorated? There were two crossed battle-axes hung on one side of the fireplace, two crossed battle-axes on the other. There was a round Scottish shield on one wall, a round Scottish shield on the other. And there was a stand of armour guarding one side of the hearth, and an empty space on the other. Nothing will make me believe that a man who arranged all the rest of that room with that exaggerated symmetry left that one feature of it lopsided. There was almost certainly another man in armour. And what has become of him?"
He paused a moment, and then went on in a more matter-of-fact tone:
"When you come to think of it, it's a very good plan for a murder, and meets the permanent problem of the disposal of the body. The body could stand inside that complete tilting-armour for hours, or even days, while servants came and went, until the murderer could simply drag it out in the dead of night and lower it into the moat, without even crossing the bridge. And then what a good chance he ran! As soon as the body was at all decayed in the stagnant water there would sooner or later be nothing but a skeleton in fourteenth-century armour, a thing very likely to be found in the moat of an old Border castle. It was unlikely that anybody would look for anything there, but if they did, that would soon be all they would find. And I got some confirmation of that. That was when you said I was looking for a rare plant; it was a plant in a good many senses, if you'll excuse the jest. I saw the marks of two feet sunk so deep into the solid bank I was sure that the man was either very heavy or was carrying something very heavy. Also, by the way, there's another moral from that little incident when I made my celebrated graceful and cat-like leap."
"My brain is rather reeling," said Granby, "but I begin to have some notion of what all this nightmare is about. What about you and your cat-like leap?"
"At the post office to-day," said Father Brown, "I casually confirmed the statement the baronet made to me yesterday, that he had been there just after closing-time on the day previous--that is, not only on the very day we arrived, but at the very time we arrived. Don't you see what that means? It means that he was actually out when we called, and came back while we were waiting; and that was why we had to wait so long. And when I saw that, I suddenly saw a picture that told the whole story.'
"Well," asked the other impatiently, "and what about it?"
"An old man of eighty can walk," said Father Brown. "An old man can even walk a good deal, pottering about in country lanes. But an old man can't _jump_. He would be an even less graceful jumper than I was. Yet, if the baronet came back while we were waiting, he must have come in as we came in--by jumping the moat--for the bridge wasn't lowered till later. I rather guess he had hampered it himself to delay inconvenient visitors, to judge by the rapidity with which it was repaired. But that doesn't matter. When I saw that fancy picture of the black figure with the grey hair taking a flying leap across the moat I knew instantly that it was a young man dressed up as an old man. And there you have the whole story."
"You mean," said Granby slowly, "that this pleasing youth killed his father, hid the corpse first in the armour and then in the moat, disguised himself and so on?"
"They happened to be almost exactly alike," said the priest. "You could see from the family portraits how strong the likeness ran. And then you talk of his disguising himself. But in a sense everybody's dress is a disguise. The old man disguised himself in a wig, and the young man in a foreign beard. When he shaved and put the wig on his cropped head he was exactly like his father, with a little make-up. Of course, you understand now why he was so very polite about getting you to come up next day here by car. It was because he himself was coming up that night by train. He got in front of you, committed his crime, assumed his disguise, and was ready for the legal negotiations."
"Ah," said Granby thoughtfully, "the legal negotiations! You mean, of course, that the real old baronet would have negotiated very differently.
"He would have told you plainly that the Captain would never get a penny," said Father Brown. "The plot, queer as it sounds, was really the only way of preventing his telling you so. But I want you to appreciate the cunning of what the fellow did tell you. His plan answered several purposes at once. He was being blackmailed by these Russians for some villainy; I suspect for treason during the war. He escaped from them at a stroke, and probably sent them chasing off to Riga after him. But the most beautiful refinement of all was that theory he enunciated about recognizing his son as an heir, but not as a human being. Don't you see that while it secured the _post obit_, it also provided some sort of answer to what would soon be the greatest difficulty of all?"