They spent another twenty minutes searching but found nothing of any further use.

“Well then,” Trounce said, “we'll take our leave of you, Mr. Keller.”

“Aye, an' ah'll not be sad t' see thee go,” the householder muttered.

As they descended the stairs, he added, “Ee were expectin' t' come int' brass, ee were.”

Trounce stopped. “What?”

“Pimlico. Ee were expectin' brass-were goin' t' pay me what ee owed in rent, or so ee said.”

“Money? From where?”

“Durn't knah.”

Outside the house, the Yard man looked up at the sky, which was now a pale overcast grey.

“As from today I'm officially on extended leave,” he said, “but I'll be damned if I'll leave this alone.” He turned to Burton and Swinburne. “Next stop, Farrow Lane. I want to know why Pimlico was released.”

They climbed back into their vehicles and took to the air. Once again, they had to search for a constable to give them directions. Fifteen minutes later, they landed outside the police station and Burton and Swinburne waited in their vehicles while Trounce entered to make his enquiries. He was gone for twenty minutes, during which time the poet discussed his latest project, Atalanta in Calydon, with his friend.

“I'm moved to heighten the atheist sentiment by way of a tribute to old Bendyshe,” he said. “He was determined to drive the last nails into the coffin that Darwin built for God.”

“Tom would have appreciated that,” Burton responded. “For all his larking around, he never had anything but praise for you, Algy, and he adored your poetry. He was one of your most dedicated advocates.”

An uncharacteristic hardness came to the poet's eyes. “Do you remember me once telling you about how, in my youth, I wanted to be a cavalry officer?”

“Yes. Your father wouldn't allow it, so you climbed Culver Cliff on the Isle of Wight to prove to yourself that you possess courage.”

“That's right, Richard. And at one point, I hung from that rock face by my fingertips, and I wasn't afraid. Since that occasion, I have never once shirked a challenge, no matter how dangerous. I don't baulk at the idea of warfare; of engaging with the enemy; of fighting for a principle. As a poet, my roots are deeply embedded in conflict.”

“What's your point, Algy?”

“My point is this: as of now, I'm on a mission of vengeance.”

The Royal Naval Air Service Station was situated some twenty miles east of Fryston. It had originally been established for the building of dirigibles, an endeavour the Technologists had abandoned after a sequence of disastrous crashes and explosions. Those failures had led to the development of rotating-wing flight mechanics, and a breathtaking example of that particular form of engineering ingenuity currently dominated the largest of the station's landing fields.

HMA Orpheuswas the most colossal rotorship Sir Richard Francis Burton had ever seen. Side-on, she appeared long and flat, two decks high, with a humped cargo hold slightly to the rear of centre, a conning tower at the front, and a glass-enclosed observation deck occupying her pointed prow. Eight flight pylons extended from either side of her-a total of sixteen, which made her the most powerful rotorship ever constructed.

Most of the crew and passengers were already aboard, ready for the short trip to London. Burton, Swinburne-sans laurel wreath-Captain Lawless, and Detective Inspector Trounce stood at the base of the boarding ramp, bidding farewell to Monckton Milnes and Sir Richard Mayne. The latter, nervous of flying, had opted to ride the atmospheric railway to the capital later in the week.

“So the fat Prussian bailed Pimlico out,” Trounce told the police commissioner. “He gave his name as Otto Steinruck, and an Essex address.”

Swinburne added, “Probably false.”

“No,” Trounce said. “The address had to be verified before his bail could be accepted. It exists and it's registered in his name.”

“You're off duty now, Detective Inspector,” Mayne said, “but if you want to pursue this in an official capacity during what little time you have left before your departure, then you have my permission.”

“I would, and thank you, sir.”

Mayne nodded, then looked up at the ship. “What a monster!” he exclaimed.

“The first of a new breed,” Lawless told him. “Mr. Brunel surpassed himself with this one!”

“And she'll take you all the way along the Nile?”

“Unfortunately, no.”

Burton said, “Mechanical devices refuse to function in the Lake Regions, Chief Commissioner. Some sort of emanation prevents it. Henry Morton Stanley's rotorchairs were found there, and their engines were as dead as a doornail. We fear that if the Orpheusflew too close she'd drop like a stone, and since we have no clear idea of where the zone begins, we have little choice but to go in on foot.”

“Besides which,” Lawless added, “this ship sacrifices economy for speed, so she'll need to stop for fuel, which can't be done in Central Africa.”

“So what's your route?” Monckton Milnes asked.

“Our first leg is London to Cairo,” Lawless replied, “the second Cairo to Aden, then we'll fly to our final stop, Zanzibar, where the collier ship Blackburnawaits us with a hold full of coal. The expedition will disembark, we'll refuel, offload the vehicles and supplies on the mainland, and head home.”

Burton added, “A hundred and fifty Wanyamwezi porters have been hired in Zanzibar and are already making their way inland with supplies purchased on the island. They'll deliver the goods to a village in the Dut'humi Hills and will await our arrival. When we get there, they'll be paid and fresh porters from the nearby Mgota tribes will be hired. We'll then push on and, hopefully, will reach Kazeh before we have to abandon the vehicles. From there, we'll hike north to the Lake Regions and the Mountains of the Moon.”

Lawless said, “Well, chaps, we'll never achieve any of that if we don't get under way, so I'd better check that my ship is flight ready. We'll be off in ten minutes. I'll leave you to say your goodbyes.” He gave a nod to Mayne and Monckton Milnes, touched a finger to the peak of his cap, and walked up the ramp and into the Orpheus.

Sir Richard Mayne drew Trounce aside and engaged him in a quiet conversation.

Monckton Milnes grasped Swinburne's hand and gave it a hearty shake. “Good luck, young 'un,” he said. “You stay safe, do you hear me?”

“Perfectly well, old horse,” Swinburne replied. “Don't you fret about me. I'll be fine. I'm too slight a morsel for a lion or crocodile to bother with, and I plan to keep myself soaked in gin to fend off the mosquitoes.”

“Good lad! I look forward to some inspired poetry upon your return.”

Swinburne caught Mayne's eye, gave him a salute, and boarded the ship.

“Are you sure he's up to it, Richard?” Monckton Milnes asked Burton. “As much as I admire him, he's the very last person I'd expect to be trekking through Africa.”

Burton gave a wry smile. “You know as well as I do that he's far from the delicate flower he appears. He's a tough little blighter and I need his insight into the Naga business. Anyway, he'd never forgive me if I left him behind.”

“And you? What of your health? Last time you tried for the Nile you were blinded and crippled for months on end.”

“True, but mostly because John Speke was pouring huge doses of Saltzmann's Tincture into me. But that aside, we have Sister Raghavendra with us. That should make a considerable difference to our well-being.”

Monckton Milnes nodded thoughtfully. “The Sisterhood of Noble Benevolence is a confoundedly strange organisation. I've never understood how they move around the East End without coming to harm. You know there's a rumour they possess some sort of supernatural grace that protects them?”

“I've heard as much, yes. It may be that their ability to heal and soothe is, indeed, supernatural. Perhaps it's another effect of the resonance from the Naga diamonds. Whatever the explanation, I'm sure she'll prove a most valuable member of the expedition.” Burton looked up at the grey sky. “Africa again,” he muttered. “Maybe this time-”