‘Me? Listen, I didn’t do anything.’

‘You were there. Perhaps me handing you the bag of slime was the key event and not the death of the cyclist—did you tell anyone where that pink goo came from?’

‘No one.’

He thought for a bit.

‘Well,’ he said at last, ‘see what else you can find out. I’m sure the answer is staring us in the face!’

He picked up the paper and read: ‘Chimp merely pet, claims croquet supremo,’ before putting the paper down and looking at me with a twinkle in his eye.

‘This non-husband of yours—’

‘Landen.’

‘Right. Shall we try to get him back?’

‘Schitt-Hawse told me they had the summer of 1947 sewn up so tight not even a trans-temporal gnat could get in without being seen.’

My father smiled. ‘Then we will have to outsmart them! They will expect us to arrive at the right time and the right place—but we won’t. We’ll arrive at the right place but at the wrong time, then simply wait. Worth a try, wouldn’t you say?’

I smiled.

‘Definitely!’

Dad took a sip of my coffee and leaned forward to hold my arm. I was conscious of a series of rapid flashes and there we were in a blacked-out Humber Snipe, driving alongside a dark stop of water on a moonlit night. In the distance I could see searchlights criss-crossing the sky and heard the distant thump-thump-thump of a bombing raid.

‘Where are we?’ I asked.

‘Approaching Henley-on-Thames in occupied England, November 1946.’

‘Is this where Landen drowned in the car accident?’

‘This is where it happens, but not when. If I were to jump straight there, Lavoisier would be on to us like a shot. Ever played “Kick the can”?’

‘Sure.’

‘It’s a bit like that. Guile, stealth, patience—and a small amount of cheating. Okay, we’re here.’

We had reached a section of the road where there was a sharp bend. I could see how an inattentive motorist might easily misjudge it and end up in the river—I shivered involuntarily.

We got out and Dad walked across the road to where a small group of silver birches stood amidst a tangle of dead bracken and brambles. It was a good place from which to observe the bend; we were barely ten yards away. Dad laid down a plastic carrier bag he had brought and we sat on the grass, leaning against the smooth bark of the birches.

‘Now what?’

‘We wait for six months.’

‘Six months? Dad, are you crazy? We can’t sit here for six months!’

‘So little time, so much to learn,’ mused my father. ‘Do you want a sandwich? Your mother leaves them out for me every morning. I’m not mad keen on corned beef and custard, but it has a sort of eccentric charm—and it does fill a hole.’

‘Six months?’ I repeated.

He took a bite from his sandwich.

‘Lesson one in time travel, Thursday. First of all, we are all time travellers. The vast majority of us manage only one day per day. Now if we accelerate ourselves like so—’

The clouds gathered speed above our heads and the trees shook faster in the light breeze; by the light of the moon I could see that the pace of the river had increased dramatically; a convoy of lorries sped past us in sudden accelerated movement.

‘This is about twenty days per day—every minute compressed into about three seconds. Any slower and we would be visible. As it is, an outside observer might think he saw a man and woman sitting under these trees, but if he looked again we would be gone. Ever thought you saw someone, then looked again only to find them gone?’

‘Sure.’

‘ChronoGuard traffic moving through.’

The dawn was breaking, and presently a German Wehrmacht patrol found our abandoned car, and dashed around looking for us, before a breakdown truck appeared and took the Humber away. More cars rushed along the road and the clouds sped rapidly across the sky.

‘Pretty, isn’t it?’ said my father. ‘I miss all this, but I have so little time these days. At fifty daypers we would still have to wait a good three or four days for Landen’s accident; I’ve a dental appointment, so we’re going to have to pick it up a bit.’

The clouds sped faster; cars and pedestrians nothing more than blurs. The shadow of the trees cast by the sun traversed rapidly and lengthened in the afternoon sun; pretty soon it was evening and the clouds were tinged with pink before the rapidly gathering gloom overtook the day and the stars appeared, followed by the moon, which arced rapidly across the sky. The stars spun around the Pole Star as the sky grew blue with the early dawn and the sun began its rapid climb in the east.

‘Eight and a half thousand daypers,’ explained my father. ‘This is my favourite bit. Watch the leaves!’

The sun now rose and set in under ten seconds. Pedestrians were invisible to us as we were to them, and a car had to be parked for at least two hours for us to see it at all. But the leaves! They turned from green to brown as we watched, the outer branches a blur of movement, the river a soft undulating mirror without so much as a ripple. The plants died off as we watched, the sky grew more overcast, and the spells of dark were now much longer than the light. Flecks of light showed along the road where traffic moved, and opposite us an abandoned Kubelwagen was rapidly stripped of spares and then dumped upside down in the river.

‘What do you think, Sweetpea?’

‘I’d never get bored of this, Dad. Do you travel like this all the time?’

‘Never this slow. This is just for tourists. We usually approach speeds of ten billion or more daypers; if you want to go backward you have to go faster still!’

‘Go backward by going forward faster?’

‘That’s enough for now, Sweetpea. Just enjoy yourself and watch.’

I pulled myself closer to him as the air grew chilly and a heavy blanket of snow covered the road and forest around us.

‘Happy new year,’ said my father.

‘Snowdrops!’ I cried in delight as green shoots nuzzled through the snow and flowered, their heads angling towards the low sun. Then the snow was gone and the river rose again and small amounts of detritus gathered around the upturned Kubelwagen, which rusted as we watched. The sun flashed past us higher and higher in the sky and soon there were daffodils and crocuses.

‘Ah!’ I said in surprise as a shoot from a small shrub started to grow up my trouser leg.

‘Train them away from your body,’ explained my father, diverting the course of a bramble that was trying to ensnare him with the palm of his hand. My shoot pushed against my hand like a small green worm and moved off in another direction. I did the same with the others that threatened me but Dad went one step farther and with a practised hand trained his bramble into a pretty bow.

‘I’ve known students literally rooted to the spot,’ explained my father. ‘It’s where the phrase comes from. But it can be fun, too. We had an operative named Jekyll who once trained a four-hundred-year-old oak into a heart as a present for her boyfriend.’

The air was warmer now, and as my father checked his chronograph again we started to decelerate. The six months we had spent there had passed in barely thirty minutes. By the time we had returned to one day per day it was night again.

‘I don’t see anyone, do you?’ he hissed.

I looked around; the road was deserted. I opened my mouth to speak but he put a finger to his lips. At that moment a car appeared around the corner and drove rapidly down the road. It swerved to avoid a fox, skidded sideways, off the road and landed upside down in the river. I wanted to get up but my father held me with a pinched grip. The driver of the car—who I assumed was Billden—broke the surface of the river, then quickly dived back to the car and resurfaced a few moments later with a woman. He dragged her to the bank and was just about to return to the submerged vehicle when a tall man in a greatcoat appeared from nowhere and placed his hand on Billden’s arm.