Unexpected aid came to help him in this quarter, as Caranby sent a note, stating that the rubbish and debris of the fire would be removed next week, and inviting Jennings to be present.  Caranby added that Mallow had resumed his visits to the “Shrine of the Muses,” but that Mrs. Octagon still continued hostile.  Basil, however, was more friendly.  “I daresay,” commented Jennings, on reading this last sentence, “he has his own axe to grind over that money.”

It was about this time that the detective received a visit from Susan Grant.  She looked as neat and timid as usual, and appeared at his rooms one morning with a request for an interview.  “I said I would help Mr. Mallow if I could,” she said when seated.

“Oh, and have you anything likely to help him,-”

“Not exactly,” said Susan, “but I found some old papers of father’s.”

“I don’t quite understand,” said the detective, who did not see what the girl’s father had to do in the matter.

“Well, it’s this way, sir.  Father was poisoned five years ago.”

“Who poisoned him?”

“That we never knew,” explained Susan.  “Father’s name was Maxwell, but when mother married Mr. Grant she made me take that name.  It was supposed that father committed suicide, and mother felt the disgrace dreadful.  That was why she married and changed the name.  But I don’t believe father, when on the point of making us rich, would swallow so much arsenic as he did.”

“What’s that—­arsenic?” said Jennings, recalling the death of Tyke.

“Yes, sir.  It was this way.  Father was working at Rexton—­”

“At Rexton?” said Jennings impatiently, “yes, yes, go on.”

“At a house near the railway station which I can point out, mother having seen it when she went to inquire.”

“Inquire about what?”

“About father’s secret job.  He had one he used to go to for three hours every day by agreement with the foreman.  Father was very clever and could do all sorts of things.  Mother never knew what the job was, but father said it would make us all rich.”

“Yes, go on.”  Jennings looked at her, nursing his chin.

“The other day I came across some papers,” said Susan, taking a roll out of her pocket.  “And it proved to be plans of father’s secret job.  And you might have knocked me down with a feather, Mr. Jennings, when I saw on the plans the name of Rose Cottage.”

The detective jumped up, greatly excited.  “Rose Cottage!” he cried, holding out his hands.  “The plans—­the plans!”

“I brought them, as I know Miss Saxon who now has Rose Cottage, is engaged to Mr. Mallow—­”

“Haven’t you got over that nonsense yet?” said Jennings, who was looking eagerly at the plans.

“Yes, I have,” replied Miss Grant, confidentially.  “I am engaged to a rising young baker who is just a foreman just now, but we hope to save and start a shop.  Still, I promised to help Mr. Mallow, and I thought he would like to see those plans.  You see, sir, they have to do with Rose Cottage.”