This explanation took place in the sittingroom. Mrs Sellon had got Joe into the kitchen and was trying to coax him into eating a bit of something. Kirk sent Hart back to Broxford, explaining that Sellon was unwell and in a spot of trouble, and warning him not to say too much about it to the other men. He then went in to tackle his black sheep.

He soon came to the conclusion that Sellon’s chief trouble, beside worry, was sheer exhaustion and lack of food. (He remembered now that he had had practically no lunch, though ham sandwiches and bread and cheese had been [liberally provided at Talboys.) Sellon’s account of himself, when Kirk got it out of him, was that, after interviewing Williams and writing his report, he had gone straight over to Broxford, expecting to find Kirk already there. He hadn’t liked to go back to Talboys, on account of what had happened-seemed to him he was better out of the way. He’d waited about half an hour for Kirk; but the men kept asking him about the murder, and what with one thing and another he couldn’t stick it. So he’d left the station and gone down to the canal and walked about a bit by the gas-works, meaning to come back later. But then it ‘came over him’ how he’d been and gone and done for himself, and even if he could clear himself of the murder charge there were no hopes for turn. So he’d taken his bike again and gone off, he couldn’t rightly remember where or why, because he couldn’t get his mind clear, and he thought if he could just go and walk about somewhere, maybe he could think better. He remembered going through Pillington and walking over the fields. He didn’t think he’d had any special reason for going to Blackraven Wood-he’d only wandered about. He might have fallen asleep. He had had a sort of notion about chucking himself into the river, but he was afraid it would upset his wife. And he was very sorry, sir, but he couldn’t say no more than that, only that he didn’t do the murder. But, he added, oddly, if his lordship didn’t believe him, then nobody eke would.

This didn’t seem quite the moment for going into his lordship’s reasons for disbelief. Kirk told Sellon he was a young fool to go rambling away like that, and that everybody was ready to believe him so long as he was telling the truth. And he’d better go to bed and try and wake up more sensible; he’d frightened his wife quite enough as it was, and here it was close on 10 o’clock (Crumbs! and the Chief Constable’s report not written yet!); he would be over in the morning and would see him before the inquest.

‘You’ll have to give evidence, you know,’ said Kirk, ‘but I’ve seen the coroner and maybe he won’t press you too hard, on account of the investigation being in progress.’

Sellon only put his head in his hands, and Kirk, really feeling that there was little to be done with him in this state, left him. As he went out, he said what cheering things he could to Mrs Sellon, and advised her not to fidget her husband with too many questions, but to let him rest and try to keep in good heart.

All the way back to Broxford, his mind was churning over his new ideas. He couldn’t get out of his head that picture of Sellon, standing at Martha Ruddle’s cottage door, waiting-

There was only one thing that gave him comfort-a comfort altogether irrational: that one curious sentence, ‘If his lordship won’t believe me, then nobody else will.’ There was no reason why Wimsey should believe Sellon, if it came to that-there was no sense in it at all-but it had sounded, well, genuine. He could hear again Sellon’s desperate cry: ‘Don’t you go, my lord! My lord, you’ll believe me!’ Kirk, rummaging the filing-cabinet of his mind, found words which seemed to him apt. Thou hast appealed unto Caesar; unto Caesar thou shalt go. But Caesar had disallowed the appeal.

Not till Kirk, weary and patient, was writing out his report to the Chief Constable did the great illumination come upon him. He stopped, pen in hand, staring at the wall. Something like an idea, that was. And he’d been on to it before, as near as nothing, only he hadn’t properly followed it up. But, of course, it explained everything. It explained Sellon’s statement and exonerated him; it explained how he had seen the clock from the window; it explained how Noakes came to be killed behind locked doors; it explained why the body hadn’t been robbed; and it explained the murder-explained it right away. Because, Kirk told himself with triumph, there had never been any murder!

Wait a bit, thought the Superintendent, figuring the thing out in his careful way; mustn’t go too fast. There’s a big snag at the start. How can we get over that, I wonder?

The snag was that, to make the theory work, one had to assume that the cactus had been removed from its place. Kirk had already dismissed this idea as silly; but he hadn’t seen then what a lot it would explain. He had gone so far as to have a word with Crutchley, among the chrysanthemums, just as he left Talboys. He had managed the inquiry pretty well, he thought. He had been careful not to ask straight out: ‘Did you put the cactus back before you left?’ That would have drawn attention to a point which was at present a secret between himself and his lordship. He didn’t want any tails about that to get round to Sellon before he himself confronted him with it in his own way. So he had merely pretended to have mis-remembered what Crutchley had said about his final interview with Noakes. It took place in the kitchen? Yes. Had either of them gone back into the sittingroom after that? No. But he thought Crutchley said he was watering them plants at the time. No, he’d finished watering the plants and was putting back the steps. Oh! then Kirk had got that wrong. Sorry. He just really wanted to get at how long the altercation with Noakes had lasted. Had Noakes been there while Crutchley was seeing to the plants? No, be was in the kitchen. But didn’t Crutchley take the plants out to the kitchen to water them? No, he watered them just where they were, and wound the clock and came out with the steps, and it wasn’t till he’d done that that Noakes gave him his day’s money and the argument started. It hadn’t lasted more’n maybe ten minutes or so-not the argument. Well, possibly fifteen. Six o’clock was rightly Crutchley’s time to stop work-he charged five bob for an eight-hour day, barrin’ time off for lunch. Kirk apologised for his mistake: the step-ladder had confused him; he had thought Crutchley meant he needed the step-ladder to get the hanging plants out of their pots. No; the step-ladder was to get up to water them, same as he’d done this morning they was above his head-and to wind the clock, like he said. That was all. It was quite ordinary, him using the stepladder, he always did, and put it back in the kitchen afterwards. ‘You ain’t tryin’ to make out,’ added Crutchley, a little belligerently, ‘as I stood on them steps with a ’ammer to cosh the old bird over the ’ead?’ That was an ingenious idea nobody had yet thought of. Kirk replied that he wasn’t thinking anything particular; only trying to get the times clear in his head. He was glad to have given the impression that his suspicions were directed to the stepladder.

Unfortunately, then, he couldn’t begin by substantiating that the cactus had been out of its pot at 6.20. But now suppose Noakes had taken it out himself for some purpose or the other. What purpose? Well, it was difficult to say. But suppose Noakes had seen something wrong with it-a spot of mildew, maybe, or whatever these ugly things suffered from. He might have taken it down to wipe it or-But he could have done that easy enough, standing on the steps or, as he was so tall, on a chair. Not good enough. What other things could happen to plants? Well, they might become pot-bound. Kirk didn’t know whether that happened to cactuses (or was it cacti?), but suppose you wanted to look and see if its roots were growing out through the bottom of the pot. You’d have to take it out for that. Or tap the pot to see if-no; it had been given water. But wait! Noakes hadn’t seen Crutchley do that. He might have suspected Crutchley was neglecting it. Perhaps he felt at the top and it didn’t seem wet enough, and then-Or, more likely, he thought it was being over-watered. These spiky cactus affairs didn’t like too much damp. Or did they? It was annoying not to know their habits; Kirk’s own gardening was of the straightforward flowerbed-and-kitchen-stuff variety.