Maria looked back. “And that’s a good thing?”

He stepped on the accelerator. “Yes. Strap yourself in. It’s going to get bumpy.”

She pulled her seat belt taut. “Maybe because we’re not using that nice smooth road up there. I liked that one best.”

“Not an option.” Rennell swerved to avoid a clump of bushes. “We need to go through that box canyon up ahead.”

“Box canyon as in ‘boxed in’?”

“There’s an outlet on the other side, but we need to get through it before the copter gets there.”

She looked back. The helicopter was gaining on them, kicking up a cloud of sand and silt from the desert floor. “This canyon is where you planted the rest of the explosives? You think it’ll be enough to bring down that copter?”

“Not directly.”

“What does that mean?”

“Kaskov’s contact wasn’t as good as I expected. I didn’t have as much explosive material as I’d like, so I had to improvise. If we set it off in an open field, no way could we generate enough explosive energy to bring down a copter a hundred feet overhead. But here we can use the rock walls of this narrow canyon to focus the blast wave. Simple physics.”

Maria nodded. “But that also means we need to be out of this canyon when it blows.”

“You know it.” He pointed to his phone on the dash. “Take that. It’s already open to the triggering app. When I give the word, press the red button.”

Maria grabbed his phone.

The copter’s roar grew louder as it approached. Rennell gunned his engine and roared through the box canyon, dodging boulders and clumps of brush.

RAT-AT-AT-AT!

Volkov and his men were leaning out of the helicopter’s side doors, firing on them with their automatic weapons.

“Shit!” Rennell put on an extra burst of speed.

“They’re gaining,” Maria said. “We’re not going to make it.”

“It’s going to be close. Be ready with that trigger.”

As Rennell navigated the canyon’s twists and turns, the helicopter roared even louder. He looked in the rearview mirror. “I can’t see it…It’s kicking up too much sand.”

RAT-AT-AT-AT!

“We’re almost out,” Rennell yelled. “Get ready!”

Maria raised the phone.

Rennell put on an extra burst of speed and roared out of the canyon. He cut the wheel hard right. “Now!”

Maria punched the button.

BOOM!

The explosion rocked the canyon behind them. A moment later the helicopter’s roar gave way to a grinding sound and the screeching of metal against rock. Pieces of the broken blades shot from the canyon.

Tanner and Mallory’s team were waiting there with their assault rifles.

RAT-AT-AT-AT!

Gunfire erupted from the canyon.

Rennell grabbed his gun. “It isn’t over yet.”

They took positions behind their cars and aimed for the helicopter’s wreckage.

“Two survivors,” Tanner called. “They both have guns. One’s behind the rock at two o’clock, and—”

BLAMM!

Rennell fired his rifle, effectively blowing away the man behind the rock.

“One survivor,” he said dryly.