Alfie had been crying.

He was sitting on the lead roof at the top of the White Tower, the central fortress of the Tower of London, and thinking about the first time he had ever set foot here. He and Richard were nine years old, and they couldn’t have been more excited. The Tower had been closed to the public for the princes’ visit, not that they realized that, of course. This was back when they were yet to learn not everyone gets to be escorted by the police through traffic, and to be greeted by a waiting crowd of well-wishers and beefeaters standing to attention. They had the run of the place, chasing each other through the courtyards and exhibits, wrestling on the grass next to the chopping block, running, screaming, from the ravens after one of them pecked Richard’s finger. Alfie hadn’t even slowed down to look at the Crown Jewels – growing up in the palace, he’d seen plenty of dusty old gems and swords before. But he remembered that his brother had stopped, fixing the display behind the glass with a serious stare, as if he was in a trance. In the end Alfie had grown bored of waiting and left him there to go and check out the toys in the gift shop.

Now, as he gazed south over the river, Alfie wondered if Richard had already started to resent him back then. He had always thought his brother didn’t care about being the “spare”, but what if he had been wrong? What if Richard had always hated him?

Alfie couldn’t get the image of his brother changing into the Black Dragon out of his head – the twisting limbs, the rage etched across his monstrous face. He closed his eyes and gripped the railing that ran around the battlements. This was worse than the feeling he’d had when his father died. Worse than the turmoil of the Succession when he’d been sure he was losing his mind. Worse than when he had found out – thought he’d found out – that his trusted teacher Professor Lock was really a monster and his family were in terrible danger. How could he not have seen what was there right in front of him all this time? Richard had killed their father. He had tried to kill Alfie too, at the coronation. What had happened to Richard? How could the loving twin he had known his whole life have become so evil?

A whistle drew Alfie’s attention to the courtyard below. Yeoman Eshelby was letting his birds out of their cages for the day, patting them on their shiny black heads as they hopped past him. Perhaps sensing someone watching, the Ravenmaster looked up and saw the young king standing on the tower. He gave a formal nod and carried on tending to the ravens. Alfie wiped his eyes. Everyone in the Keep must know by now, he thought miserably.

Car horns blared from the traffic jam on Tower Bridge as if it were just another normal summer’s day. The Vikings hadn’t been seen since they were paid off, and the prime minister was basking in the nation’s praise. “THE DEAD REST IN PEACE!” the headlines shouted in glee as the country heaved a huge collective sigh of relief. The storms had disappeared, the sun was shining again and the only worry on the horizon seemed to be whether Kate Robertson could win her first Wimbledon title. Alfie could only imagine their panic if they knew what he knew. The Black Dragon was still out there, dreaming up dark schemes with Professor Lock, cooking up the next phase of their plan. Something terrible was coming and—

“I’m so sorry.”

Alfie had not heard the Lord Chamberlain come out on to the rooftop. He looked even older than normal. Deep worry-lines fanned across his brow like a crinkled road map.

“He tried to tell me, you know. At Ellie’s party,” said Alfie. “He said it was all my fault. Did I do this to him?”

LC moved closer, placing a hand on Alfie’s shoulder. “None of this is your fault. If it is anyone’s, it is mine. I should have seen this sooner. It makes perfect sense now.”

“Sense?” Alfie brushed his hand away. “None of this makes any sense!”

“I understand, Majesty. All I mean is the Black Dragon – how it came to be. It was Richard’s blood, the royal blood that Lock needed to combine the power of King Alfred’s crown with the dragon bones and create a new creature. That was what I was missing. It’s so obvious now.”

“But why hide who he was after the coronation? Richard could have killed me any time he wanted!”

“I don’t know, Majesty. But they went to great lengths to make sure we obtained the Raven Banner for them.”

“What do they want with that stupid flag? It doesn’t even work.”

“Not in the way we intended. But perhaps Lock knows something we don’t. Whatever it is, we must hunt them down before they have time to execute their plan. Defeat them once and for all. Lock and the Black Dragon.”

“You mean Richard?” Alfie said. There was something in LC’s troubled expression he didn’t like at all. “What is it?”

“Majesty, I have known you and your brother since the day you were born. I may not be the best at showing it, but I care for you both, very much. Perhaps if this had come to light earlier, but now…”

“What are you saying, LC?”

The old man stiffened and raised his head, as if addressing the audience at a state banquet. “Prince Richard has made his choice. He is a traitor and must be dealt with as such. The Defender must kill the Black Dragon.”

Alfie felt his legs wobble beneath him. Did LC really just say that to him? “You want me to…” Alfie could hardly bring himself to say it. “To kill my own brother?!”

“He is no longer your brother, sir. He is your enemy. And make no mistake, this is war.”

Alfie pushed past him, towards the door. “I can’t listen to any more of this.”

“Majesty, we must all stand firm and face this battle together!” LC pleaded.

Alfie swung open the door, only to march straight into Hayley. She burst on to the roof, out of breath after running up the staircase.

“Miss Hicks, now is not the time,” began LC.

But she held up her phone, silencing him. “You’d better make time. ’Cos you need to hear this. Both of you.”

She pressed play. At first all they could hear was a low rumble, like engines turning. But then an automated voice spoke:

“Leave your message after the beep.”

Alfie and LC recognized the next voice immediately, even though he was talking in an uncharacteristic whisper.

“It’s me,” said Brian’s voice on the tape. “We have the banner. We’re on the way back from Oslo now. They’re planning to use it at the handover. But keep your distance. I think the girl suspects something. I’ll call again when I can.”

The recording ended. LC and Alfie looked at each other in stunned silence.

Minutes later they sat opposite Brian in the Keep as the message played again. LC had commanded the Yeoman Warders to vacate the room, though he told two of them to guard the doors and listen out in case he summoned them. Alfie was disturbed by what he had heard, but he was sure Brian would have a good explanation. The phone message came to an end once more, and LC fixed Brian with a penetrating stare.

“Well? Explain yourself, King’s Armourer. For whom were you leaving this message?”

Brian hadn’t stopped looking at Hayley, a cold, hard expression Alfie had not seen before on his bodyguard’s face. Only now did Brian turn to the Lord Chamberlain.

“Sorry, guv, but I can’t tell you that,” he replied.

LC sprung forward. “WHAT DID YOU SAY?!” Alfie actually thought the old man was going to hit Brian. “YOU HAVE PASSED SECRET INFORMATION TO PARTIES UNKNOWN, AND YOU WILL EXPLAIN YOURSELF!”

Brian barely flinched and kept his stony silence. Nearby, Herne got up and paced back and forth, restless. The hair on his back stood up and he growled at Brian, low and deep. Alfie, his head spinning, stepped in between them.

“Please, Brian, just tell us what’s going on and we can forget it.”

Brian leant back in his chair and sighed. “Sorry, kid, no can do.”

“YOU ARE ADDRESSING YOUR SOVEREIGN!”

LC was purple with rage and he coughed and stumbled for a moment. Alfie helped him back to his chair. Hayley kept her eyes on the floor.

All were quiet for a few moments. The Yeoman Warders who had been guarding the doors had rushed in when they heard the shouting and now they stood, pikes at the ready, unsure what to do.

“Is there nothing you wish to say in your defence?” LC croaked.

Brian stared at the wall, unmoved. “No.”

LC wiped sweat from his brow with a handkerchief, his hand shaking. “Yeoman Warders, take the Armourer to the cells,” he commanded. “Inform the Jailer.”

The startled beefeaters exchanged a glance, then walked over to Brian and pulled him to his feet. Alfie looked to LC and Hayley in disbelief, but neither met his gaze.

“Wait!” Alfie shouted. “This is wrong, you can’t do this! If Brian says he had his reasons, then that’s good enough for me.”

But Brian smiled at him. “It’s OK, chief.” And then he allowed the beefeaters to escort him from the Map Room.

Alfie felt numb. First he had lost his brother. And now Brian? It felt like the cornerstones of his world were crumbling into dust, one by one. Unable to hold his tongue, he turned on Hayley.

“What have you done?” he snapped.

“What are you having a go at me for?” said Hayley, shocked. “How about ‘thanks, Hayley, for watching my back’?”

“I told you to drop it, and look what’s happened now.”

“You ungrateful little—”

Yells interrupted them from outside the Map Room. At first Alfie thought maybe it was just somebody else joining in the screaming match, but then he realized it was coming from the direction in which the Yeoman Warders had taken Brian. They rushed into the corridor to see one beefeater lying unconscious on the floor and the other doubled-up in the corner, holding his stomach and groaning.

“What happened? Where is the prisoner?” shouted LC.

A secret passageway was open in one wall, pumping out cold draughts of air. Alfie ran over to it and looked inside. It snaked away into darkness.

Brian was gone.