‘It makes sense to me,’ said Roddy. ‘I know for a fact she has a grudge against the family. And look at it this way: she and Owen go upstairs to look for Henry together – five minutes later, he’s dead. That makes them the prime suspects, in my book. What do you think, Hilary?’

‘I agree entirely. Apart from anything else, have you noticed the way they’ve been looking at each other all evening? Lots of little meaningful glances have been passing back and forth. I don’t think this is the first time they’ve met at all. I think they’ve known each other all along.’

‘Well, is this true?’ said Thomas. ‘Have you two met before?’

Phoebe gazed at Michael helplessly, before admitting: ‘Well, yes … We did meet once. Years and years ago. But that doesn’t mean —’

‘Ha! So now it’s all coming out!’

‘I’ll tell you another thing,’ said Roddy. ‘Owen’s already condemned himself out of his own mouth. Hilary and I were both upstairs when Mark was found: so was Dorothy, and so were you, Thomas – looking for Pyles. Now, Owen says that he was standing at the top of the staircase looking at the suits of armour all this time. So if any of us had tried to leave the billiard room and get past him, he would have seen us, wouldn’t he? But he says that nobody came by!’

Thomas rubbed his hands. ‘All right,’ he said to Michael. ‘Talk your way out of that!’

‘There’s a perfectly simple explanation,’ he answered. ‘The murderer didn’t enter or leave the billiard room by the door. There’s a passage from that room. It leads to one of the bedrooms upstairs.’

‘What the devil are you talking about, man?’ Thomas thundered.

‘It’s true. Ask Tabitha: she knows. She knows because Lawrence used to use it, during the war.’

‘What tommyrot.’ He turned to his aunt, who had been listening to this conversation with every appearance of enjoyment. ‘Did you hear that, Aunt Tabitha?’

‘Oh yes. Yes, I heard it all.’

‘And what do you think?’

‘I think it was Colonel Mustard, in the kitchen, with the candlestick.’

‘Oh, for God’s sake,’ said Hilary. ‘We’re wasting valuable time. Dorothy hasn’t been down for half an hour or more: we must try to find her.’

‘All right,’ said Thomas, getting up. ‘But these two aren’t coming with us.’

The curtains in the dining room could only be opened and closed by means of a thick cotton rope. Thomas cut off two lengths from this and lashed Michael and Phoebe securely to their chairs. Care of the prisoners was left to Mr Sloane (and Tabitha, for what she was worth), while Roddy, Hilary, Thomas and Pyles set off to search the house, agreeing to meet back in the dining room in twenty minutes’ time.

Hilary was the first to return, followed shortly by the butler.

‘Any luck?’ she asked him.

Pyles shook his head. ‘You won’t be seeing her again,’ he said, in his most lugubrious tone. ‘Not on this side of the grave.’

Roddy arrived with more bad news.

‘I went out to look in the garages. I thought she might have driven off without telling us.’

‘And?’

‘Well, her car’s still there, but it wouldn’t be any use to her in any case. One of those huge beech trees has blown right over, and the driveway’s completely blocked. So now we’re all well and truly stuck.’

Michael laughed. ‘What did you expect?’ he said. He was still tied to his chair, and not in the best of tempers. ‘We psychopaths think of everything, you know.’

Roddy ignored him. ‘I’ve had a thought, though, sis: what about your plane? Could we get away in that?’

‘Well, I can’t fly the thing,’ said Hilary. ‘And my pilot’s staying in the village tonight. He won’t be round till the morning.’

‘Do you mean Conrad?’ asked Phoebe mischievously. ‘I should like to meet him again.’

Hilary gave her a furious look, and Roddy couldn’t resist explaining, with a smirk: ‘Conrad got the push a few months ago – on Sir Peter’s orders. His replacement isn’t quite in the same league.’

‘Do you think he could possibly take me for a ride, when he comes round tomorrow?’ cried Tabitha, her eyes alight with anticipation. ‘I love aeroplanes, you know. What sort is it?’

‘A Buccaneer,’ said Hilary.

‘The Lake LA-4-200, I suppose? With the four-cylinder Avco Lycoming engine?’

‘Oh, shut up, you old fool.’

Hilary picked a grape from the fruit bowl and began tossing it nervously between her hands.

‘Now there’s no need to get bad tempered, you naughty girl,’ said Tabitha. ‘A kind word and a happy smile don’t cost much, do they? Always look on the bright side, I say. Things could easily be so much worse.’

‘Aunty,’ said Hilary slowly. ‘We’re trapped in an isolated house, with a homicidal maniac, in the middle of a thunderstorm. All the phone lines have been cut off, we have no means of escape, two of us have been killed and another has gone missing. How could things possibly be worse?’

At that moment, the lights went out and the house was plunged into darkness.

‘Oh God,’ said Roddy. ‘What’s happened?’

The blackness to which they had been consigned was absolute. The heavy dining-room curtains were closed, and it was impossible to see even an inch or two ahead in such thick, impenetrable gloom. To add to the eeriness of the situation, it seemed to all of the company that the sounds of the raging weather outside had increased tenfold as soon as their powers of vision were taken away.

‘It must be a fuse,’ said Pyles. ‘The fuse box is in the cellar. I’ll see to it at once.’

‘Good man,’ said Roddy.

Whether he would succeed on this mission seemed open to doubt, for his progress towards the door was marked by any number of thuds, crashes, smashes and tinkles as he collided heavily with various objects of furniture scattered around the room. But finally he made it: the door creaked open and shut, and they could hear his receding footsteps echoing faintly as he made his halting way across the stone-flagged hall.

Then the clicking of Tabitha’s needles resumed, and she started humming another tune. This time it was ‘The Dambusters’ March’.

‘For God’s sake, Aunty,’ said Roddy. ‘How on earth can you do any knitting in Ulis dark? And would you kindly desist from singing those infuriating songs?’

‘I must say, Mr Owen, your ingenuity compels admiration,’ said Hilary; and her brother could recognize in her voice a forced, brittle cheerfulness – a sure sign that her spirits were violently agitated. ‘I can’t help wondering what sort of fate you had in mind for the rest of us.’

‘I hadn’t really thought, to be honest,’ said Michael. ‘I was more or less improvising the whole thing, you see.’

‘Yes, but surely you must have had a few ideas. Henry’s back; Mark’s arms. What about Thomas? What part of his anatomy were you intending to go for?’

‘Where is Thomas, anyway?’ said Roddy. ‘He should have been here ages ago. The last I saw of him he –’

‘Ssh!’ It was Hilary who cut him short. The atmosphere in the room grew suddenly tense. ‘Who’s that moving about?’

They all strained to listen. Was that a footstep they had just heard? Was there someone (or something), in the room with them, a furtive, watchful presence, creeping through the inky shadows – and now very close at hand? Was that the sound of something on the table itself – where they were all sitting, rigid with expectation – being very quietly, very stealthily moved?

‘Who’s there?’ said Hilary. ‘Come on, speak up.’

Nobody breathed.

‘You were imagining it,’ said Roddy, after about a minute.

‘I don’t imagine things,’ Hilary answered, indignantly. But the tension had gone.

‘Well, fear can play strange tricks,’ said her brother.

‘Look: I am not afraid.’

He laughed scornfully. ‘Afraid? You’re scared witless, old girl.’

‘I don’t know what gives you that idea.’