“At last my chance came,” Jack went on. “I’d found out almost everything; not, of course, exactly by way of legal proof, but to my own entire satisfaction: and I determined to lay the matter definitely at once before Mr. Callingham. So I took a holiday for a fortnight, to go bicycling in the Midlands I told my patients; and I fixed my head-quarters at Wrode, which, as you probably remember, is twenty miles off from Woodbury.

“It was important for my scheme I should catch Mr. Callingham alone. I had no idea of entrapping him. I wanted to work upon his conscience and induce him to confess. My object was rather to move him to remorse and restitution than to terrify or surprise him.

“So on the day of the accident—call it murder, if you will—I rode over on my machine, unannounced, to The Grange to see him. You knew where I was staying, you recollect—”

At the words, a burst of memory came suddenly over me.

“Oh yes!” I cried. “I remember. It was at the Wilsons’, at Wrode. I wrote over there to tell you we were going to dine alone at six that evening, as papa had got his electric apparatus home from his instrument-maker, and was anxious to try his experiments early. You’d written to me privately—a boy brought the note—that you wanted to have an hour’s talk alone with papa. I thought it was about ME, and I was, oh, ever so nervous!”

For it all came back to me now, as clear as yesterday.

Jack looked at me hard.

“I’m glad you remember that, dear,” he said. “Now, Una, do try to remember all you can as I go along with my story... Well, I rode over alone, never telling anybody at Wrode where I was going, nor giving your step-father any reason of any sort to expect me. I trusted entirely to finding him busy with his new invention. When I reached The Grange, I came up the drive unperceived, and looking in at the library window, saw your father alone there. He was pottering over his chemicals. That gave me the clue. I left my bicycle under the window, tilted up against the wall, and walked in without ringing, going straight to the library. Nobody saw me come: nobody saw me return, except one old lady on the road, who seemed to have forgotten all about it by the time of the inquest.”

(I nodded and gave a start. I knew that must have been Aunt Emma.)

“Except yourself, Una, no human soul on earth ever seemed to suspect me. And that wasn’t odd; for you and your father, and perhaps Minnie Moore, were the only people in the world who ever knew I was in love with you or cared for you in any way.”

“Go on,” I said, breathless. “And you went into the library.”

“I went into the library,” Jack continued, “where I found your father, just returned from enjoying his cigar on the lawn. He was alone in the room—”

“No, no!” I cried eagerly, putting in my share now; for I had a part in the history. “He WASN’T alone, Jack, though you thought him so at the time. I remember all, at last. It comes back to me like a flash. Oh, heavens, how it comes back to me! Jack, Jack, I remember to-day every word, every syllable of it!”

He gazed at me in surprise.

“Then tell me yourself, Una!” he exclaimed. “How did you come to be there? For I knew you were there at last; but till you fired the pistol, I hadn’t the faintest idea you had heard or seen anything. Tell me all about it, quick! There comes in MY mystery.”

In one wild rush of thought the whole picture rose up like a vision before me.

“Why, Jack,” I cried, “there was a screen, a little screen in the alcove! You remember the alcove at the west end of the room. It was so small a screen, you’d hardly have thought it could hide me; but it did—it did—and all, too, by accident. I’d gone in there after dinner, not much thinking where I went, and was seated on the floor by the little alcove window, reading a book by the twilight. It was a book papa told me I wasn’t to read, and I took it trembling from the shelves, and was afraid he’d scold me—for you know how stern he was. And I never was allowed to go alone into the library. But I got interested in my book, and went on reading. So when he came in, I went on sitting there very still, with the book hidden under my skirt, for fear he should scold me. I thought perhaps before long papa’d go out for a second, to get some plates for his photography or something, and then I could slip away and never be noticed. The big window towards the garden was open, you remember, and I meant to jump out of it—as you did afterwards. It wasn’t very high; and though the book was only The Vicar of Wakefield, he’d forbidden me to read it, and I was dreadfully afraid of him.”

“Then you were there all the time?” Jack cried interrogatively. “And you heard our conversation—our whole conversation?”

“I was there all the time, Jack,” I cried, in a fever of exaltation: “and I heard every word of it! It comes back to me now with a vividness like yesterday. I see the room before my eyes. I remember every syllable: I could repeat every sentence of it.”

Jack drew a deep sigh of intense relief.

“Thank God for that!” he exclaimed, with profound gratitude. “Then I’m saved, and you’re saved. We can both understand one another in that case. We know how it all happened!”

“Perfectly,” I answered. “I know all now. As I sat there and cowered, I heard a knock at the door, and before papa could answer, you entered hastily. Papa looked round, I could hear, and saw who it was in a second.

“‘Oh, it’s you!’ he said, coldly. ‘It’s you, Dr. Ivor. And pray, sir, what do you want here this evening?’”

“Go on!” Jack cried, intensely relieved, I could feel. “Let me see how much more you can remember, Una.”

“So you shut the door softly and said:

“‘Yes, it’s I, Mr. Callingham,’” I continued all aglow, and looking into his eyes for confirmation. “‘And I’ve come to tell you a fact that may su............