Anna followed Garrick from the security of the air traffic control tower and headed back out into the drizzling rain. Silence extended between them like a high-tension wire.

Frustration sang in her blood at their current impotence as they exited the airport grounds and entered an industrial area, car showrooms and tool depots crowding the road around them. Her mind buzzed with the certainty of what she’d just seen: the younger queens preparing to leave, gathering before establishing new colonies.

“We need to do something, now,” she muttered as they half jogged, half walked through the wet air.

Garrick’s voice was laced with exasperation. “What do you suggest?”

She craned her neck to check the view. Now they were back at ground level, there was nothing to see. Just a vast expanse of dirty buildings. Her thoughts kept returning to Julia and the Sweeper Device. It was large enough to decimate the entire hive, provided it was placed at the very heart.

“What if we went there and—”

“You know as well as I do we don’t have enough weapons. It’s suicide, just the two of us. We need back up and more weapons. Even then…” His voice trailed off wearily. “What if you’re wrong?”

Anna stopped abruptly and stared him down. “I am not wrong. I know insect behaviour, and the Chittrix may have arrived from God-knows-where, but there are enough commonalities.” Her tone was adamant. She tapped her foot on the ground, her arms folded tight across her chest. “There is something you don’t know about.”

Garrick waited, visibly working the muscles in his jaw.

“Julia was working on resonant frequencies and using them to power explosives.”

He listened without comment, his lips pinched.

“I didn’t know who the hell you were,” her voice rose, defensive. “The first time I saw you, you were stealing my armour. You could easily have been a scavenger taking advantage. I was hardly going to launch into some detailed discussion of all the tech we’d been working on.” She reached out and touched his hand. “Now it’s different. We’re on the same side.”

He rubbed his eyes with the back of his wrist. When he opened them again, his face was calm.

“What is it?”

Anna started walking again, setting a brisk pace, her enthusiasm giving her a new burst of energy. “Julia took sound-cannon technology and adapted it into a bomb. The Sweeper. It’s powerful enough to destroy the hive and all the young queens inside.”

Garrick followed, his face serious, silently absorbing this new information.

He didn’t ask any questions, so she continued. “The Sweeper uses high-peak power pulses to broadcast waves of hypersonic sound. Each Chittrix resonates at a particular frequency. As the Sweeper broadcasts through a continual range, this allows it to resonate with every individual insect. If the frequency is powerful enough and matches the frequency of the insect, then the insect will literally explode.”

“Right.” His voice was deadpan while they walked further, skirting mangled grass and litter lying sodden on the boggy dirt. “Is it safe?”

“The sound frequencies don’t harm humans or animals, just insects. The issue is that we’ve only trialled it on a small scale. Earth insects. Not Chittrix. It’s a prototype, but if it worked, it would decimate the Chittrix in the hive. I’m not even sure how much of the hive is biological in construction; there’s a chance it could damage that as well.”

“That’s a lot of hypotheticals, Anna.”

“I know, but the Sweeper is our only realistic option. Do you have any better suggestions?” She massaged her temples, rubbing at the tender muscles under her skin.

Garrick remained silent, his face telling her there was nothing at the Command Base with power to match.

“Only the emerging queens will be on the surface.” His jaw tightened at her words. “There’s likely to be many more still in the process of hatching. Any egg chambers will be the deepest within the colony. Any serious attempt to wipe out the new queens must target the centre of the hive itself.”

Finally he grunted, whether in affirmation or disbelief, she wasn’t sure.

“So where is this device?”

“In Julia’s backpack.”

Garrick halted abruptly, but Anna barely noticed now she was in full swing.

“It needs to be attached to a coding chip to work. Julia and I both carry one.” She tugged a chain from her pocket. Attached to it was a small silver lozenge. When she looked up, Garrick had come to a halt several feet behind her.

“With help from your men, we can break into the hive and trigger the device. Stop the queens from flying.”

“Anna—”

She cut him off, ignoring his pissed-off face. “We have to at least try.”

He rubbed his eyes. “I can’t believe you didn’t mention this before.”

“I’ve explained why,” she said, struggling to contain her irritation. She spun on her heel and stomped to the nearest car showroom. Glaring into the smashed dimness of the window, she sucked in deep breaths to slow her racing pulse.

“Nothing useful here.” His words caressed the skin of her nape as he guided her away from the window, his palm pressed against the small of her back. His fingers slipped under her chin, forcing her to look him in the eye.

“I’m sorry. I should have told you,” she said.

He took her hand, pressed it to his warm lips and kissed her fingers, firing a quiver of heat right to her core. A half smile lit up his face but as he began to speak his reply was lost in the battle cry of a Chittrix plummeting towards them.