‘This’ll be easy. I’ve done it before and I know exactly where we need to be.’ He pointed down to the stern.

‘But why are we here at all?’ Lexi seemed less troubled by the swaying of the crow’s nest than Al. Even a small movement down on the ship meant a lot of movement up here. ‘Surely the job’s done. “Okay” doesn’t go any further into the past than 1839.’

‘Fair question.’ Will reached back to grab the edge of the crow’s nest as it swayed the other way. ‘It didn’t take much to start “okay”, but it took a lot to keep it going. It might have died out if they hadn’t used it as a soap name, for instance. And for it to last until the soap came along, Van Buren had to be Old Kinderhook. And for that he needed to have been born in Kinderhook. So welcome to the early 1600s, where we might just find out how that came about. The man on that raised deck in the high boots and fancy collar is Henry Hudson. He’s English, but working for the Dutch East India Company. They’re exploring the river. The ship’s called the Half Moon. One day they’ll name the river after him. He doesn’t know that, and he doesn’t know he’ll disappear in two years’ time, searching for the Northwest Passage. I looked him up in Encyclopaedia Britannica after I got home. Do you do that?’

‘Something like it,’ Lexi said. ‘Wait till you see.’

‘The deck’s called an aftercastle. That’s where we need to be. The one at the front’s a forecastle.’ Will could picture the illustrations in the encyclopedia, a portrait of Hudson next to an engraving of the Half Moon – Halve Maen in Dutch – with Mohican canoes approaching from the shore. Hudson hardly looked like the portrait at all, but the Half Moon was close enough.

‘So why exactly are we up here and not down there?’ Al was feeling queasy and could have done without the lesson in ship parts. He already knew all that.

‘Another fair question. Take a look at the top of the cliffs.’ Will searched until he could find the exact spot, and then pointed. There were children crouched in the long grass and staring down at the deck of the ship. ‘We wouldn’t have the “k” in “okay” if it wasn’t for them. Let’s go to the aftercastle and watch it happen.’

He led the way down the rope ladder, and when they reached the deck he said, ‘Pick up a rope or something and look like you know how to use it.’

Lexi found a mallet lying next to some wooden pins. It was only once it was in her hand that she realised she could use it as a weapon if she needed to. ‘Okay’ had been a relief from that point of view – no battles, no threats to their lives so far. She checked the crew. There were no weapons in sight. She should have made sure of that earlier from the crow’s nest, but Will seemed so confident she’d stopped thinking that way.

As they reached the rear deck, they saw Henry Hudson wave to the cliff-top and the children ducked down out of sight. One by one, they cautiously stood up again.

‘We’ll call this bend Children’s Corner,’ Hudson announced.

The navigator picked up a quill, dipped it in ink and wrote on the chart in front of him. He was mapping the river as they travelled.

‘Kinderhoek,’ he said. A glow rose from the page, at the tip of his quill.

Will walked straight up to him and said, ‘Sir, I’ve been sent by the second lieutenant. Your sextant has fallen and broken below decks. He thinks it can be repaired, but he’d like you to give instructions.’

‘What? How?’ The navigator wasn’t happy. ‘No one should be touching my sextant. It was in my quarters. How—’ He was already walking off. He stopped and turned. ‘Captain, permission to leave the aftercastle—’

Hudson nodded.

With the navigator gone, Will, Lexi and Al stepped forward to the chart. The ‘h’, ‘o’ and ‘e’ in ‘Kinderhoek’ were pulsing brightly, with an ‘m’ fitting among them to make the word ‘home’.

‘I wonder,’ Will said. For a moment, he dared to hope it would mean home for him too.

He picked up the quill and wrote ‘x2’ next to the initials ‘WH’ near the corner of the chart. ‘TH’ had been written just below. He set the quill down, touched the glowing letters in ‘Kinderhoek’ and the portal opened. Al already had the peg in his hand.

From nowhere, fog rolled up the river and across the deck, and the Half Moon shuddered in a wind that wasn’t there.

Lexi, Al and Will blew clear of the deck and into the sky. Will laughed. It was his first flight to the future for four years and there had been many days and nights when he had doubted whether he would ever make another.

The pictures of passing time rushed by – railways and revolutions, factories and fishing fleets. As they fell towards Fig Tree Pocket in the 21st century, it was clear there were still three of them. Will wasn’t going back to 1918 yet.

They dropped towards the roof of their house and Lexi shouted, ‘This way!’ and steered past it. They landed in the ferns at the side.

In the dark inside Al’s bag, Doug tried to work out which way was up. He smelt creek mud, cut grass and sausages. He was home.

‘Not exactly London in the early 20th century,’ Will said, looking around. ‘That was probably a bit much to hope for. But it’s good to be moving again. Great, actually. I can come with you next time, can’t I?’

‘Every time.’ Lexi stood up and brushed dirt off her pants. ‘It’ll be good to have you there. You look more ready for a fight than we are. Except right now maybe, when you look like some hot skater dude.’ She laughed.

‘A hot skater dude? We didn’t have a lot of those in 1918. As far as I know. Whatever they are.’ Will checked what he was wearing, but it didn’t help. ‘Skater dude’ remained a mystery. He had a black Von Dutch cap on, an orange T-shirt with skulls on it and baggy three-quarter pants. ‘I’m going to assume it’s legal to be one, unless you tell me otherwise.’

Al felt his phone vibrate in his bag and then it started to ring. It was Mursili.

‘You’re back,’ Mursili said. ‘Good. I didn’t know what I was going to tell people if it went through to the message area. What happened? Was it 19th century? Did you find your grandfather?’

Al watched Will stand up and straighten his cap. Lexi picked a leaf off his shoulder and blushed.

‘Pretty much 19th century and no. But we found the guy from Nantucket in the 1830s. We’ve brought him back with us.’

‘What? Another one?’ Mursili sounded excited. ‘You’re bringing everyone from the past to the present, one by one? Put me on wide speaker. I want to talk to him. What’s his name?’

Al pressed the loudspeaker icon on screen and the phone beeped. ‘Will, there’s someone who wants to—’

‘Ahoy! Ahoy!’ Mursili shouted, making Will recoil. ‘Will? Is that right? Mursili here. Did you ever do “water”? I was the librarian in Hattusa.’

Will still looked wary. ‘Is that – Do I—’

Lexi stepped in. ‘It’s a phone. That’s a phone in the 21st century. A telephone.’

‘Seriously? This isn’t some—’ Will reached for the phone and took it from Al. He turned it over to check for wires and then took a close look at the screen. ‘It’s nothing like a telephone. Not one of the standard bits of the telephone’s there.’

‘You should try coming from 3,000 years ago,’ Mursili’s voice said. ‘You must be from some time much closer if you have a phone.’

‘1918. Do I just—’ Will pointed to the phone. Al nodded.

‘1918. So easy.’ Al turned the volume down, but Mursili’s voice was still pretty loud. ‘If you meet oncoming oxen at a crossroads in 1918, do you have to sacrifice? No. If you build a new house, do you have to bury a goat’s placenta beneath the corner posts or risk the wrath of the god Naamek? No. And Naamek’s no pushover. Always wanting more placenta.’

Lexi tried to explain it. ‘We brought Mursili here—’

Mursili cut in again. ‘And now I’m on the team, Will. I’ll help you adjust. I’m team librarian. When “okay” went off, Al and Lexi called me and I looked it up for them. You had movies in 1918? I’m like that guy in the control room with all the screens who goes in and shoots all his scenes in one day.’

‘Mursili, we’ll—’

‘We’ll have to meet.’ Mursili was already onto his next idea. ‘You might have knowledge that’ll let us fine-tune what we do.’

‘Good. Tomorrow, Mursili,’ Al said clearly. ‘Tomorrow. We’ll sort out a time in the morning.’

‘Good. Very good. Tomorrow. Ahoy, then.’ With that he was gone.

‘The guy in the control room with the screens—’ Will looked baffled.

‘Sorry,’ Lexi said. ‘That was a bit too much 21st century at once, wasn’t it? Mursili still hasn’t worked the phone out. He’s from 1180BC. He doesn’t realise you have to leave spaces, take turns, things like that. And he and Al are trying to bring back “ahoy” for answering the phone, which is a bit embarrassing.’

‘Ah, Alexander Graham Bell.’ Finally something sort of made sense. ‘Really?’

‘Just for “hello”,’ Al said, as if that made it all right. ‘I don’t do it for “goodbye” or anything. That was all him.’ Lexi and Will were both laughing. ‘It didn’t feel so nerdy till right now.’

They took leftover sausages to Will once dinner had finished. It wouldn’t have worked to turn up with a 19-year-old guy as their new friend and expect their parents to feed him.

He slept in the ferns that night. It was summer and no one ever went down that side of the house. He said he’d done far worse over the past four years.

The following day was Sunday, and Lexi and Al insisted to their parents that they’d been planning all week to meet friends for a movie at the El Dorado. Lexi even showed where it was on the calendar in the kitchen. She had written it there the night before. Their mother offered to drive them, but they said that’d be embarrassing, since everyone else was catching the bus.

Al hated catching the bus. He knew his mother would bring up the conversation any time he wanted a lift in future. ‘But wouldn’t it embarrass you?’ she’d say. ‘Wouldn’t you be much happier on the bus?’ It would work for now, though.