In about an hour and a half they reached their destination, and Jimmy, who knew the district from his visits to the Drews, saw with satisfaction that the point was where the Halford-London road crossed that which passed over the river bridge above the Cranshaw Falls. From there to the Old Ferry was about ten minutes’ smart walk, and, if the taxi-man’s statement was correct, Cosgrove could therefore have reached Austin’s boat about 9.25. It would take him ten minutes or more to row to the Luce Manor boathouse, so that he would arrive there, say, between 9.30 and 9.40. This was quite sufficiently in accordance with the statement of Lucy Penrose and young Potts that they had seen the boat arriving about half-past nine. Jimmy recognised delightedly that the whole thing was working in. It was still about quarter to twelve, and Jimmy had the taxi run slowly on to the Old Ferry lane. Lois was already there, and he lost no time in putting her in possession of the facts. ‘You guessed that this happened?’ he queried. ‘Yes. I suddenly thought of it in bed, the night before I came up to see you.’ ‘But I can’t make head nor tail of it,’ Jimmy confessed. ‘Now it seems that Cosgrove must have been at the boathouse between half-past nine and ten, and yet he caught the 10.30 from King’s Cross, where he couldn’t have arrived till at least 11.30. The thing’s an absolute puzzle to me. Can you see light?’ ‘Of course. He never caught the 10.30 at all.’ ‘But, my dear girl, he did—he must have. You forget the porter at Grantham and the dealer at Montrose.’ ‘Not at all. He travelled no doubt by the 10.30 from Grantham to Montrose. But that’s a very different thing. I’ll tell you, Jimmy, what’s puzzling you. You haven’t studied your Great Northern time table as I have. The 10.30 is not the only train in the day from London.’ Daunt waited. ‘Well?’ he said impatiently. ‘Before that 10.30, as you might have known from Mr Tanner’s story of his own movements, there runs a pick-up train. It leaves King’s Cross at 10.00 and reaches Grantham at 12.28, ten minutes before the 10.30. And that train, Jimmy, stops at three or four stations. It stops’—she leant forward and whispered in his ear with an air of triumph—‘_it stops at Hitchin at 10.45!_’ ‘And Hitchin is only six miles from here! Good Heavens, how stupid not to have seen that! Of course that’s what he did! After the murder he motored to Hitchin and caught the relief train. Well, Lois, you deserve all you’re going to get for thinking of it!’ ‘But we’re not quite out of the wood yet,’ the girl reminded him. ‘We have to find out how he went from here to Hitchin.’ ‘Probably by the taxi,’ suggested Daunt, and they returned to where the vehicle was waiting. But his guess was incorrect. The driver assured them that on reaching the cross-roads Cosgrove had paid him off and he had returned at once to London.