“I’m not surprised to hear you say that Miss Trevert has been doped,” Robin remarked. “I found her here in a house on the outskirts of Rotterdam in the hands of two men, one of whom is believed to be implicated in a mysterious case of suspected murder in England. Through the part he played this morning, he has probably run his head into the noose. But he’ll have it out again if we delay an instant. I told the manager that yarn about the dentist to avoid enquiries and waste of time. I have here a note from some man I don’t know, addressed to Miss Trevert, warning her of a grave danger threatening her. It corroborates to some extent what I have told you. Here ... read it for yourself!” He handed the doctor the note signed “W. Schulz.” The doctor read it through carefully. “What I would propose to you,” said Robin, “is that we two should go off at once to this Herr Schulz and find out exactly what he knows. Then we can decide what action there is to be taken ...” He paused for the doctor’s reply. The latter searched Robin’s face with a glance. “I’m your man,” he said shortly. “And, by the way, my name’s Collingwood ... Robert Collingwood.” “There’s a car downstairs,” said Robin, “and a guide to show us the way. Shall we go?” Five minutes later, under the newsboy’s expert guidance, the car drew up in front of the small clean house with the neat green door bearing the name of “Schulz.” Leaving the boy to mind the car, they rang the bell. The door was opened by the fat woman in the pink print dress. Robin gave the woman his card. On it he had written “About Miss Trevert.” Speaking in German the woman bade them rather roughly to bide where they were, and departed after closing the front door in their faces. She did not keep them waiting long, however, for in about a minute she returned. Herr Schulz would receive the gentlemen, she said. Within, the house was spotlessly clean with that characteristic German house odour which always seems to be a compound of cleaning material and hot grease. Up a narrow staircase, furnished in plain oil-cloth with brass stair-rods, they went to a landing on the first floor. Here the woman motioned them back and, bending her head in a listening attitude, knocked. “_Herein_!” cried a guttural German voice. The room into which they entered would have been entitled to a place in any museum for showing the mode of life of the twentieth-century Germans. With its stuffy red rep curtains, its big green majolica stove, its heavy mahogany furniture, its oleographs of Bismarck, Roon, and Moltke, it might have been lifted bodily from a bourgeois house in the Fatherland. A man was sitting at a mahogany roll-top desk as they entered. The air in the room was thick with the fumes of the cheap Dutch cigar he was smoking. He was a sturdily built fellow with blond hair shaven so close to the skull that at a distance he seemed to be bald.