Christine gauged the mother's affection by the eagerness of the voice and eyes. She had never seen Mrs. Erskine show her heart so clearly, and her own went out warmly to the widowed, childless woman before her. “Mrs. Erskine,” Christine moistened her lips, “there's been a strange mistake somewhere. That looks like a letter from Robert, but it isn't! He never wrote those lines. Never!” “What?” Mrs. Erskine turned very pale—“what do you mean?” The half-sheet which she held in her hand shook till Christine wondered that it did not rattle. “You see, _I_ wrote Rob's Christmas letter for him four years ago. He had burnt his hand badly at the mills, and couldn't go anywhere, so that we had a quiet time together, like old times. He dictated a letter to you and I wrote it. Jack can tell you the same thing. Besides, you might have known that Rob couldn't—wouldn't have written like that.” Mrs. Erskine seemed dazed. “But—but—they were all alike. All his letters were the same. . . . And who's Jack?” “A friend of mine who used to know Rob well—in Canada. I'm so sorry to've sprung this on you, but you ought to know it, and at least you can comfort yourself with the thought that your son never wrote such horrible letters as you have been thinking all these years. Surely someone with you must have had a motive to intercept your son's letters, and forge others in their stead.” “It's his paper—the paper he always used.” Mrs. Erskine seemed quite dazed. She gave Christine the impression of a woman speaking in a nightmare. “It may be, but it's not his letter. You see, I happen to be in a position to swear to that one, and to prove it in time. Lots of other people knew of his accident. Now, Mrs. Erskine, who is there who could have done so wicked, so cruel a thing?” Mrs. Erskine suddenly got up, as though she found the room stifling. She looked ghastly, and to Christine she looked frightened as well. “I must be alone—this shock—this blow—I want time”—she held out a cold, shaking hand—“will you come back—it's now five. Will you come back at seven without fail? Without fail? I—promise me you won't speak of this to anyone in the meanwhile. I know a French detective, not so far from here, before whom I want to lay the case. He is the only man who can solve this riddle. But I'll go into that later when you come back. Promise that you won't speak of it to anyone in the meanwhile. I have a feeling that absolute secrecy is essential if this mystery is to be unravelled,—and unravelled it must be—and quickly!” Christine would have taken the widow's hand, but Mrs. Erskine did not see her gesture. There was something fierce in her eyes. Action, not sentiment, was evidently rising rapidly in her heart to the exclusion of any softer feeling. Christine mentally apologised to her for ever having thought her dull and cold. “But what about the Inspector?” she asked gently.