"Doctor Ashton suggested that you should come round to the surgery. Then you can have some grub and drive up with us." Joe shook his head. "Thankin' yer kindly, but if it's all the same I reckon I'll meet yer there. I gotter couple o' torfs comin' to the Palace for a lesson this mornin', an' it means a quid to me if I let 'em knock me abaht a bit." "That's all right," said Colin, "as long as I can depend on you to keep the appointment." "I'll be there, doctor," replied Joe. "I'll be there, honest to Gawd. You bring the young laidy along in the car, and yer'll find me sittin' on the Embankment waitin' for yer." Satisfied with this assurance, Colin took his departure, and, retracing his steps to the end of the street, made his way back to Shadwell by the same route that he had come. As he opened the door of the house he saw to his surprise that the note which he had left for Nancy was still lying on the hall table. Before he had time to realize anything further Mark suddenly appeared from the surgery. "Hullo!" exclaimed Colin. "I made sure you'd be out on your round." "So I ought to be," replied Mark, "but, as a matter of fact, I was waiting for you." "What's the matter?" "I'm rather worried about Nancy. She's never turned up, and there's been no message from her." Colin's whole figure stiffened abruptly. "No message?" he repeated. "Nothing. I can't understand it at all. If she's ill, surely she'd have let us know." Without a word Colin swung round sharply, and, striding toward the pegs, unhooked his coat. "What are you going to do?" demanded Mark. "I'll get out the car and drive up there at once," he said. "Can you stop in for another twenty minutes? I'll telephone you directly I find out what's the matter." Mark nodded. "Keep steady, old son. I expect it will be all right. There's probably some quite simple explanation." Colin moistened his lips. "We were mad ever to let her leave the house," he said hoarsely. "If any harm's come to her I'll kill Fenton with my own hands." As he spoke the clock on the stairs chimed out eleven-thirty, and, turning hastily to the door, he hurried out again into the street. If there is any truth in the theory that each of us possesses a guardian angel, the fact that a quarter of an hour later Colin drew up safely at the corner of Jubilee Place must be regarded as an amazing tribute to the efficiency of his own particular escort. Leaving the car in the gutter, he jumped out on to the pavement, and the next moment he was mounting the narrow staircase which led up to the first landing. There were two studios on this floor, the one which Nancy rented being distinguished by a small brass knocker. Catching hold of the knob, Colin rapped loudly, and then, bending down, lifted up the flap of the letter box. "Nancy," he called out, "are you there? It is I--Colin." There was no answer.