"I know--I feel sure that Ortmann suspects us. Why does he live as Mr Horton over at Wandsworth Common?" "Because he is so infernally clever," laughed the air-pilot, in his cheery, nonchalant way. Neither of them knew, up to that moment, anything more of Mr Henry Harberton, of Park Lane, save reading in the papers of his social distinction. Neither Kennedy nor his charming well-beloved had dreamed that Ortmann, alias Horton, patriotic Britannia-rule-the-Waves Englishman, was identical with that meteoric planet in the social firmament of London, Mr Henry Harberton, whose wealth was such that even in war-time he could give two-guinea-a-head luncheons to his friends at one or other of the half-dozen or so London restaurants which cater for such clients. Seymour Kennedy was driving the car swiftly, but Ella, nestling beside him, took no heed of the direction in which they were travelling. The night-wind blew cold and he, solicitous of her welfare, bent over and with his left hand drew up the collar of her Burberry. They were leaving London ere she became aware of it, travelling westward, branching at Hounslow upon the old road to Bath, the road of Dick Turpin's exploits in the good old days of cocked-hats, powder-and-patches, and three-bottle men. Passing through Slough, they crossed the river at Maidenhead and again at Henley, keeping on the ever ascending high-road over the Chilterns, to Nettlebed, until they ran rapidly down past Gould's Grove through Benson, and past Shillingford where, a short distance beyond, he pulled up and, opening a gate, placed the car in a meadow grey with mist. Afterwards the pair, leaving the high-road, turned into a path which led through the fields down to the river. Reaching it at a point not far from Day's Lock, they halted. Before them, between the pathway and the river's brink, there showed a lighted window obscured by a yellow holland blind, the window of a corrugated iron bungalow of some river enthusiast, the room being apparently lit by a paraffin lamp. Carefully, and treading upon tiptoe, they crept forward without a sound, and, approaching the square, inartistic window, halted and strained their ears to listen to the conversation in progress within. Words in German were being spoken. Ella listened, and recognised her father's voice. Ortmann was speaking, too, while other voices of strangers also sounded. What Seymour overheard through the thin wood-and-iron wall of the riverside bungalow quickly convinced him that Ella's suspicions were only too well founded. A desperate conspiracy to commit outrage was certainly being formed--a plot as daring and as subtle as any ever formed by the Nihilists in Russia, or the Mafia in Italy.