'Tell me again how the hell we ended up in this mess,' Lewis shouted at him over the roar of the flames. The stairwell was full of smoke. There was no way down.

James grabbed his arm.

'By ignoring every piece of safety training we've ever received,' he shouted back, and dragged his Inspector away from the entrance. They were both beginning to cough hard. Time was running out. 'We've got to get to the roof.'

'Might be a fire escape,' Lewis agreed, pressing the tongue of his tie over his mouth and nose.

They toiled up the concrete steps, through the rising fumes. James' heart was thudding, his gut roiling. It was dawning on him that if there was no fire escape, or the one there was had been damaged already, they would have little choice. He would have little choice.

He'd kept his secret so long. Nursed it like a baby. He'd come to hate having to lie to Lewis. The man was his friend. More than a friend. The man who knew him better than anybody ever had, or ever would. James was under no illusions about his feelings for his boss, even though he knew they could never be reciprocated. He knew that time, and what had been mostly his own mistakes, had strengthened the tie between them to tempered steel. No matter how strong it might be, though, there were some things that could not be overlooked. He had lied to Lewis. Even if it was by omission, it was still a lie. And he knew that Lewis would be deeply wounded to realise that James had not shared with him this, his last, his deepest secret.

Lewis flung open the fire door at the top of the staircase. They stumbled out onto the flat roof of the building and stood, bent over, trying to get their breath. Smoke billowed up around them from the lower windows of the office block, cocooning the square roof in thick, grey cloud. The air wasn't much cleaner up here, but the sharp wind and the sleet felt good on James' skin. He could already feel the tightness of his lungs, the stickiness of blockages caused by melting plastics and paints all around him.

They had to get out.

He rested his hand on Lewis' back. 'You okay?'

The older man nodded, though he clearly wasn't. He made a gesture with his hand, an order to search for an escape route. One that James was pretty sure would no longer exist. So he staggered around the perimeter of the roof, leaning over the low parapet to see if he could find a way, while down below he could hear the wail of fire sirens. There would be crowds by now, of course. People love a show, especially in a city. People with mobile phones. People with mobile phones with cameras.

He found the fire escape. It was, as he had expected, woefully inadequate, broken half way down, and he cursed the inspecting officer who should have enforced better protection on the building before it came to this. Even so, he said a quiet prayer of thanks that at least it was night, and they were the only ones caught in this death-trap. Except of course, for Neil Furston, the murderer they had been seeking. It was he who had set the fire, in a mountain of packing waste abandoned on the first floor. The place was well ablaze before James and Lewis had realised their mistake, and any exit via the lower staircases was blocked. It was the roof, or nothing.

But they were seven storeys up. Too high to jump. No nearby roofs to leap to. There was nothing for it.

'What hell are you doing?' Lewis's voice was hoarse and shocked as James strode towards him over the roof. The tar beneath the felt was melting, warming under his feet. 'The whole lot's going to cave in!'

James was already stripping off his clothes.

'Bit late for a sunbathe, lad,' Lewis rasped.

'Sorry, sir, I would have told you-' He slipped the last pearl button of his shirt and pulled it off his shoulders. The binder underneath was fastened with Velcro, the work of a moment to rip apart. And then his wings unfurled, stretching out. He gave them a few flaps, to warm the muscles up after being so tightly constrained for so long – it felt like a lifetime since he'd put the binder on before work that morning.

'I've never taken passengers before,' he went on, the downdraft from his feathers swirling the smoke around them. 'I hope I can manage it. You'll just have to hang on. At the very least it'll be controlled fall, which is less damaging than jumping outright.'

At that point, he heard a hoarse laugh, and looked up. Lewis was staring at him, yes, but with the biggest grin on his face James had ever seen. Rage condensed inside him.

'I didn't expect ridicule from you at this point, sir,' he snapped. 'Not when I'm trying to save your life!'

Lewis shook his head, chuckling. 'It's not that, lad. What are the bloody odds, eh?

And he pulled his own shirt out of his trousers and revealed what was underneath.

That familiar structure of spandex, Velcro and plastic restraint boning.

James stood there stunned, unable to move or speak, as Lewis stripped off first his jacket, and then his shirt and tie, and the binder. Naked to the waist, his wings stretched out, dark as a crow's, luminous as a magpie's, the perfect, shimmering negative of James' own pale golden quills.

'Well, don't just stand there flapping like a bloody chicken,' Lewis said. 'Better take our binders with us. Not easy to come by.'

'There'll be cameras,' James finally managed. 'People with mobiles. We'll be all over Facebook in minutes.

'I'd rather that than roasted,' Lewis pointed out. 'Besides, I never had anyone to fly with before. We could always just fly away?'

'Your chest. You need to see a doctor,' James said, and suddenly became aware that there were tears in his eyes. 'I don't want to lose you.'

Lewis stepped forward and gently folded him for a moment against his skin. Grey hairs tickled. Cold rain stung their flesh.

'Not going anywhere,' he breathed in James' ear. 'Specially not now. Got a few flying tips to pass on, haven't I?'

Suddenly, there was a crash, and the door to the stairwell blew open, belching flames.

Lewis craned his head around and looked up into James's eyes.

'Time to fly,' he said.

And winked that familiar, mischievous wink that James knew so well.

They stood on the edge of the parapet, as close as their wingspans would allow, hugging the bundles of their clothes and binders to their chests. They looked at each other.

'There's a lot of smoke,' James called to his boss. 'Camouflage. We might get away with it.'

'Land in the alley, and put our normal clothes back on like Superman, you mean?' Lewis grinned. 'We should be so lucky.'

'Together, then?'

Lewis nodded. The tip of his inky wing extended, and for a second brushed James' dorsal feathers tenderly.

They jumped.

For a second, everything was plunging, terror, wind, suffocating, smoke, blindness. And then the updraft took him, lifting. He spread his wings as wide as he could and managed three mighty beats. And then he was out on top of the smoke cloud, the heat buoying him up, the angry orange glare of the street lights, mixed with the firelight, painting livid colours on the undersides of his feathers. For a second he was calm. And then he panicked:

Where was Lewis?

He circled, and on his second turn, he saw a shape emerge from the cloying grey column, dark and magnificent, each wingbeat a marvel. With stately grace, Lewis wheeled and soared out over the rooftops and away. And with his heart singing, James followed, just as he always did.