As they grubbed around in the thin earth of the back garden, everything seemed to have gone unnaturally quiet, as if in anticipation of some kind of massive impact. Their little corner of Foxbridge was always quite peaceful, but right then, it felt as though the Earth was silently waiting for some catastrophic event. The skies were empty; not even a tiny plane buzzed overhead. Traffic seemed to have come to a halt, and there was almost no sound of human habitation. Just birds chirping their melodies, and insects busy pollinating the spring flowers. No music blared from radios, no phones rang, no television shows played on large flat screens. The hubbub of human life had stopped abruptly—as though people themselves had been totally erased, leaving the Earth to be taken over by other life-forms.

But something about the sinister quality of the silence made George think it wasn’t going to last. The minutes ticked by, and the longer he waited for the silence to break, the more worried he grew.

Daisy and the twins had come out to help in the garden, but they were all just standing there quietly, watching George and Annie fill their buckets with leaves and roots.

“Daisy,” ordered Terence, coming out into the garden, “I want you to take the twins inside and start packing whatever supplies we have to carry down to the basement. We need dry food, water, windup flashlights—anything you can stash down there. We may need to stay underground for days on end—we can’t risk coming back up. We’ll take the radio and hope that transmissions will resume to let us know that the chaos is over.”

Daisy nodded, ushering Juno and Hera inside with her. Even they seemed intimidated by the strange atmosphere.

Susan returned from next door, bringing with her not just armfuls of bedding but a person; a very elderly and disheveled-looking person who was just recognizable as the former code-breaker George and Annie had met with Eric a few days earlier.

“I found her on the doorstep,” said Susan, sweeping past them and heading for the basement with the bedding.

“Beryl!” exclaimed Annie in astonishment. “What are you doing here?”

“I didn’t know where else to go,” she admitted. “And I thought that if anyone could explain what in heaven’s name is going on, it would be Eric.”

“He’s not here,” Annie told her. “He’s the ‘Information Technology Czar’ so he had to go and meet the PM.”

“Tsk! What silly titles they give people these days!” said Beryl, who despite her appearance seemed remarkably bright-eyed, almost as if she was enjoying herself. “Well, isn’t this fun. Reminds me of the good old days!”

“You’ll have to go down to the basement,” said Annie. “I don’t think George’s dad will let you hang around up here.”

“Oh, marvelous!” enthused Beryl. “It will be just like the Blitz all over again! I do hope there’s some sherry down there!” With incredible agility, she headed down the steps into the basement, humming a favorite wartime tune as she went.

“What are we going to do?” Annie hissed to George as she picked up her bucket.

“Where’s Cosmos?” he asked urgently.

“Still indoors. Shall we just leave him there?”

“I think we should get him,” said George.

“But he’s evil!” squeaked Annie. “He’s turned to the dark side!”

“I know that . . . But we might be able to use his own rules on him, to help us out. I think we should get him.”

“Okay.” Annie slunk inside with her bucket and returned a few moments later, showing George that she had stashed Cosmos, the world’s greatest computer, under a pile of salad leaves. “But I still don’t get what we’re actually going to do,” she whispered.

George, however, had been formulating a plan. “I want you to take Ebot up to the tree house, as though he’s going to be the watch person,” he said. “And then come back as if you’re heading down to join our families in the basement.”

“What do you mean?”

“We’ll pretend we’re going to live in the basement with them,” said George. “But then we’ll lock them in and stay outside ourselves.”

“Lock them in?” gasped Annie in horror.

“We have to! If we don’t, there’s no way they’ll let us crack this. Our parents will make us hang out with them and eat thermoses of soup and sing stupid songs, while outside, the whole world will fall to pieces! And we won’t be able to do anything about it.”

“What can we do?” asked Annie. “Isn’t this all getting a bit big for two kids?”

“No, Annie!” said George firmly. “I thought that before, but there’s no one else here to do it, and we have to try. Even your dad isn’t having any effect. We’ve got to do something, Annie. Like Beryl—if she hadn’t helped to crack that code during the war, millions more people would have died. So even if we just do something small, it might make a difference.”

“You’re on,” said Annie, squaring up her shoulders, impressed by his words. “In that case, I’m with you. I’m not going to hide in a basement. I’m going to help. We can do this. We can.”

Soon the little back garden was as bare as on a winter’s day. No edible leaf was left on a stalk. Every shred of vegetable life had been plucked, pulled, dug up or cut, then bundled down the stairs to the basement to form part of their supplies for what could be a long stay.

By now Daisy had taken the twins safely downstairs, and they were listening to her read them their favorite book about a caterpillar who couldn’t stop eating on Saturdays.

As she read by the light of her flashlight, Terence and Susan were busy arranging the final details of their hideaway, while Annie passed snacks, water bottles, and comic books down through the trapdoor.

“You two go down there,” she insisted bossily. Terence wasn’t the only one able to summon his inner tyrant at will. “That’s it! Right down. And I’ll pass the rest of the stuff to you. Oh look, here’s George! He can finish off.” She gave him a very meaningful look. “I’ll take Ebot up to the tree house and install him,” she said very clearly. “And then, when I come back down, George and I will follow you down to the basement. Capisce?”

The adults nodded solemnly, too focused on their own plans to turn the basement into a comfortable and cozy living space to suspect the pair of treachery.

Annie rescued Ebot, who had been left forlornly deactivated in the sitting room. She found and jammed Eric’s space helmet onto the robot’s head and, half supporting him, staggered over to the tree house ladder, which was fortunately lowered. She propped the android Eric against the tree while she felt around in her pockets for the remote access glasses, put them on, and used the eye-gaze control to wake Ebot out of his sleep.

He came alive with a jerk and a squawk.

“Climb the ladder,” Annie instructed him.

Stumbling and awkward, Ebot started to ascend the swaying ladder, like an ungainly spider in a space suit scaling a wall. Annie shimmied up after him with the bucket containing Cosmos. Ebot fell rather than climbed onto the platform; Annie leaped over him, setting the bucket down, then went over to look through George’s telescope. The town still appeared quiet and sleepy, but a frisson in the air told her that thunder, of one sort or another, was on its way.

“Wait here,” she instructed her robot friend, before shinnying back down to the ground again and running over to where George was hovering by the double trapdoor that led to the basement.

Looking down, she gazed at the upturned faces: her mother, George’s parents, and the two small girls. Suddenly she knew that George wouldn’t actually be able to do what was needed. And in that second, she also realized that it was her turn to be brave and act on her words.

“I’m sorry,” Annie mouthed. And then she flipped both doors down and shot the bolt across before the people in the basement had a chance to stop her. She just had time to see the look of shock on their faces. And then they disappeared from view, sealed into the underground hidey-hole.

But they were not sealed for sound. “Hey!” Terence banged loudly on the door from below. “What do you think you’re doing? You can’t stay up there. Open the doors! Open the doors, I say!”

“Sorry!” Annie shouted down toward the basement. “We’ll explain. Later.”

She grabbed George and wheeled him round to face the back door. “Run!” she said.

A lone voice floated after them: it was Beryl. “Well done, you two! Good luck!”

Together, they pelted toward the tree house, scrambled up the ladder, and drew it up behind them. They both automatically lay down on the platform, out of sight from below. As an afterthought, George reached up and pulled Ebot down beside them. Now anyone looking up from the ground would just see an empty tree house, inaccessible to anyone but the birds and the most sure-footed of climbers.

At this point neither George nor Annie could have said exactly why they behaved as they did; their instincts for survival seemed to have taken over, prompting them to take cover.

Their instincts were sound: they had reached their treetop hideaway with only seconds to spare. As they lay there, panting and breathless, they heard a noise in the distance that got louder and louder as it approached George’s house. At first it was just white noise; they couldn’t differentiate individual sounds. But soon they could make out shouts, crashes, yelps, explosions, and thuds.

“What is it?” Annie was trembling. George’s idea of remaining outside the sanctuary of the basement had been a brave one, but she wondered now if it had been sensible. This was seriously scary.

Annie didn’t need to wait for an answer. Underneath the tree house, the ground shook as a gang of looters invaded the back garden, flattening the fences and churning up the ground as they charged across. They smashed windows and doors, rampaging through the houses in their search for food. From their hideaway the pair heard dogs barking, then screams as people got hurt. As they peered out of the tree house, they saw the mob fighting for possession of the few items left behind by householders who had already fled the area. Luckily they passed through quickly—although it felt like hours to Annie and George. Within minutes the gang had moved on down the row of houses until they were out of sight.

“Yowza!” whispered Annie. “That was nasty. Your dad was right about the danger.”

George breathed out heavily. The pounding of his heart had almost blocked out the noise of the rioters. “Good call,” he agreed, “to get everyone into the basement.” He couldn’t bear to think what might have happened to his little sisters and parents, to Beryl and Annie’s mom, if they hadn’t hidden. He hoped that Eric really was in some kind of übersafe location with the Prime Minister, and not out on the streets, but he thought it was better not to mention this to Annie. Things were bad enough without adding other fears as well.

“Do you reckon they’re okay?” whispered Annie, her voice trembling.

“Yup, they’re fine,” said George confidently. To his surprise, once his heart rate dropped, he started to feel much better. While the riot was going on, he’d wondered if he was going to stay frozen to the platform with fear forever. But now that he knew it was time for him and Annie to leap into action, he suddenly found within himself a whole extra stock of bravery. “Probably a bit dusty, but I don’t think anyone found them. They just ripped straight through the kitchen and out the other side.”

“What now?” asked Annie quietly.

Below them, in the ravaged garden, a few stragglers charged across the flattened fences, pausing to hurl the odd stone through the few remaining unbroken windows, before taking off again.

“They’re just smashing anything they can.” Annie was disgusted.

“That’s why we need to be quick,” said George. “If anyone sees us up here, we could be in big trouble. I mean, big-like-the-universe trouble.”

“Be quick with what?”

“We’ve got to try again,” George replied. “You know, if at first you don’t succeed . . . ! Your idea about getting Ebot captured so we could see who this I AM is and what it is up to is the best we’ve got. But this time we need to give Cosmos more specific instructions so that he places Ebot somewhere he’ll be found.”

“So we’ve got to carry on doing my chemistry project?” asked Annie in amazement. The world was falling to bits, and she was still doing her homework! It was so normal and yet so weird all at once that she couldn’t quite take it in. “Even though it’s apocalypse time?”

“Yup.” George was amazed at his own confidence. “We’ll tell Cosmos we need to work on the next element of life, and then we’ll send Ebot through the door-way. . . . Ebot is wearing your Dad’s space suit already, so the fact that your dad is traveling through the space portal should be broadcast out there. Isn’t that how I AM found us before?”

“You’re right!” Annie got Cosmos out of the bucket, brushed off some lettuce leaves and a small slug, opened him up, and pressed the power button.

“Do we need our suits?” asked George.

“Um, we might,” Annie realized. “It depends. But they’re in Dad’s study.”

George was already letting down the rope ladder.

“You can’t!” she squeaked. “It’s too dangerous! What if they come back?”

“I’ll be very quick,” said George confidently. “Get Cosmos working and open up the portal. I’ll be back in a nano-flash.”

“Okey-doke,” said Annie as he disappeared from view. “Let’s get this show on the road . . . Cosmos!” She took a very deep breath as the computer came to life. “I want to carry on with my chemistry project. I want you to look for amino acids in space. I want you to summon the space portal and open the doorway onto a comet in the Solar System where I can find amino acids, which are the building blocks of life.”