"Their names are Seeker and von Brünig, and they're living in a small bungalow on Sheppey. They are supposed to be artists. As a matter of fact, von Brünig is a captain in the Germany Navy. I don't know who the other man is; I think he has been sent over specially about the powder."

Her statement fitted in so exactly with what I had already found out from Latimer and Gow, that I hadn't the remotest doubt she was telling me the literal truth. Of its importance—its vital importance to England—there could be no question. I felt my heart beating quickly with excitement, but the obvious necessity for fixing on some scheme of immediate action kept my brain cool and clear. The first thing was to gain a moment or two to think in.

"You realize what all this means, Sonia?" I said. "You're quite prepared to throw over your father and McMurtrie? You know how the doctor deals with people who betray him—when he gets the chance?"

"I am not afraid of them," she answered defiantly. "They are nothing to me; I hate them both—and Hoffman too. It's you I want. You are the only man I ever have wanted." She paused, and I saw her breast rising and falling rapidly with the stress of her emotion. "We will go away together—somewhere the other side of the world—America, Buenos Ayres—oh, what does it matter where?—there are plenty of places! What does anything matter so long as we love each other!"

She half rose to her feet, but I jumped up first.

"One moment, Sonia," I said. "Let me think."

Thrusting my hands in my pockets, I strode across the room, and pulling up in front of the little window, stared out across the marsh. As I did so, I felt as if some one had suddenly placed a large handful of crushed ice inside my waistcoat. About two hundred yards away, strolling cheerfully and unconcernedly towards the hut, was the charming but painfully inopportune figure of Joyce.

It was a most unpleasant second. In my excitement at listening to Sonia's revelations, I had clean forgotten for the time that Joyce was coming, and now it was too late for the recollection to be of much practical use. Except for an earthquake, or the sudden arrival of the end of the world, nothing could stop her from reaching the hut in another five minutes.

I stood quite still, racking my brains as to what was the best thing to do. It was no use trying to signal to her from the window, for Sonia would be certain to see me; while if I made some excuse for going outside, Joyce would probably call out to me before I had time to warn her. My only hope seemed to lie in the chance of her hearing us talking as she came up to the door, in which case she would know at once that there was some one there and go straight on to the Betty.

I had just reached this conclusion when a queer sound behind me made me spin round as if I had been struck. Sonia, who had risen to her feet, was standing and facing me; her whole attitude suggestive of a highly-annoyed tigress. I don't think I have ever seen such a malevolent expression on any human being's face in my life. For an instance we stood staring at each other without speaking, and then quite suddenly I realized what was the matter.