“I have made enquiries about workmanship and materials,” he went on. “From what I have heard, the railway navvies are too skilled to use inadequate materials of any kind. Not only their reputations and future livelihood would depend on it, but their lives at the time. They have built railways all over the world, and there is no known example of a bad one anywhere.”

She lifted her eyes quickly to gaze into his face. “Then where is the secret profit coming from?” she demanded. “This is not enough, Mr. Monk! If the materials are good, then perhaps there was dishonesty in acquiring them?” She was watching him intently, her face burning with emotion. He realized again how deeply she was in love with Dalgarno, and how terribly afraid that he would be driven into crime and then ruined by it, not only morally but in every other way, perhaps even to end in prison like Arrol Dundas. Monk knew the bitterness of that only too well. It was one thing of which even his shattered memory had not completely let go.

He offered her his arm, and after only a moment’s hesitation she took it and they walked side by side between the flower beds.

“I haven’t looked closely at the possibility of land fraud yet,” he said, speaking quietly so passersby, strolling in the bright day, would not overhear him. He was aware of their curiosity, politely masked as courteous nods and smiles as they passed. He and Katrina must make a striking picture, both handsome people, elegantly dressed and obviously involved in a conversation of deep emotional content.

She kept her hand lightly on his arm, a delicate gesture, one of trust rather than familiarity. “Please look into it, Mr. Monk, I beg you,” she said urgently. “I am desperately afraid of what may happen if no one learns the truth before it is too late. We may be able to prevent not only the tragedy of an innocent man’s being implicated in a crime, but the loss of an untold number of people’s lives in the kind of disaster that only something like a rail crash could bring.”

“Why do you fear a crash, Miss Harcus?” he asked, frowning a little at her. “There is no reason whatever to think there is either faulty material or workmanship. If there is land fraud, then that is dishonest, certainly, but it does not cause accidents.”

She lowered her eyes and turned away until he could no longer see her face except in profile, and her hand slipped off his arm. When she spoke it was barely audible.