"Mercia," I said, "when are the Tregattocks expecting you back? Soon?"
She nodded her head. "I told them I should be away for a few days. I did not know how long."
"Well, it seems to me," said I, "that the best thing we can do when we get to London is to drop you at an hotel. Then you can go back to them to-morrow, as if you'd just come from Woodford."
"And you?" she asked anxiously.
"I must go back to Park Lane. Whatever happens, I must stay there for another fortnight."
"But it is madness," she whispered fearfully; "more than ever madness now. Do you think Rojas will forget—"
"No," I interrupted, smiling; "I'm quite sure he won't forget for a long time. All the same, I've no intention of running away. I shall have Billy with me, and we're a fairly useful combination." Then I looked straight into her eyes. "Mercia," I said, "why did you come to Woodford?"
"Guarez sent for me," she answered simply. "He said that you were to die the next day, and I thought that perhaps I might save you."
"But why did he want you?" I persisted.
"I think he guessed," she said slowly. "Da Costa saw us that night in Park Lane, and since then Guarez has suspected that you cared for me. He meant to use me—how do you say?—as a decoy. I was to bring you to the Hollies, and once there—" She shivered.