Flying a sky bison was nothing like flying an airplane, and Asami knew which one she preferred. Oogi bobbed slightly up and down as they glided through the frigid air of the Southern Mountains. Although this was hardly her first time on one of the animals, Asami had never lost the feeling that one wrong move would send her tumbling off. She was perched on Oogi's neck in the pilot position Tenzin used, reins in a white-knuckled grip, squeezing as tight as she dared with her knees. Why no one had thought to install seat belts—or any basic safety equipment as far as she could tell—was beyond her.
Asami ventured a glance back. The Northern Water Tribe's encampment stretched out far below, the light of the spirit portal a blazing spear up into the dark sky. Even from this height, it was obvious that the camp was a mess. Mecha tanks were strewn about like a child's toys, and she could see tiny waterbenders running back and forth to douse the many smoldering tents. Asami felt a flush of pride at the thought that she had given a camp full of highly-trained benders such a thorough thrashing. It hadn't all been her, of course, but the approach had been her idea and, at least on the destruction side, it had clearly worked.
Asami's plan had been simple in theory, if in reality quite dangerous. She would borrow a plane from Future Industries' sometime-partner Varrick, who had come in by air himself the previous day (thankfully also allowing her to preserve the deception that Asami had arrived on his latest cargo ship). The bulk of Varrick's supplies had been weapons of one sort or another to support the South, and among these she had found a number of the small remote-detonating explosives he had designed earlier that year. With these in hand she'd somehow convinced Bolin, and then finally Mako, that they could stand on the wings of her plane as she flew in low and slow towards the Northern Water Tribe encampment. The approach of a biplane would be loud and obvious, especially echoing through the mountains at night, and would hopefully draw the fire of any forces defending the spirit portal. If that weren't enough, they would use a combination of the plane's guns, Mako's firebending, and Varrick's explosives to make sure they got Unalaq's attention.
Under the cover of this distraction, the other members of Team Avatar would fly in on Oogi and head straight to the spirit portal. Tenzin believed that if Korra could close the portal again, Unalaq's plans would be shut down for good—it didn't seem like he could reopen either portal without the Avatar's help. If Asami, Mako, and Bolin could keep Unalaq and his troops distracted, it would give Korra the kind of time and access she needed to focus on closing the southern portal for good. In some ways, Asami thought, it was simply Mako's concept of redirection on a larger scale.
Behind her, Chief Tonraq groaned. All things considered, Asami thought that was probably a good thing. At this point, she would take all the good news that she could get. Considering how badly Korra's father had been injured, if he was making noise that meant he was at least conscious. He had been lucid enough when they'd left the others, but Asami hadn't been fooled. The chief needed medical attention, and quickly.
They had come in hard, with Asami, Mako, and Bolin attempting the distraction while Tenzin flew Oogi to the portal. At first, it had worked. She'd raked back and forth across the camp, focusing first on taking out the mecha that formed the bulk of their defenses. In truth, it was easier than she'd dared hope. When she'd flown in she'd noticed a large number of mecha tanks towards the back of the camp and a row of tents in front of them that appeared to have been burned. For whatever reason, these tanks hadn't joined the fight. It was a good thing, too; she wasn't sure that they would have gotten in at all if they'd had a few dozen more machines to handle.
Their advantage hadn't lasted for long, however. Although Asami and the two benders had been able to distract the soldiers well enough, the dark spirits at Unalaq's command had apparently not been fooled. As Asami banked the plane for another assault she had seen them coming, boiling out of the forest surrounding the spirit portal in a black cloud.
She knew now that they came in all shapes and sizes. While many resembled animals of a sort, similar to the bison spirit she and Iroh had seen, others were strange, angular shapes unlike anything found in nature. They had bodies of squares and triangles, their appendages nothing more than swirling, wiggling lines. There were hundreds of them.
Whether of their own initiative or at Unalaq's direction, the spirits had ignored Asami and gone straight for Tenzin and the Avatar. While the spirits didn't seem to be able to hurt Oogi while he was flying, it turned out that they could weigh him down. As they hit the giant sky bison they clung to his thick fur, then each other, their various limbs twisting and tangling as they dragged him down. In a detached way, Asami found it fascinating. The spirits could appear and disappear as they moved in and out of the spirit world at will, but once in the physical world it appeared that, although they could hover, they had mass and to follow the rules of physics like any other creature.
More and more spirits piled on, pulling Oogi, Tenzin, Korra, Bumi, and Kya to the ground. At the same time, Unalaq's two children, both powerful waterbenders, entered the fight. In an ironic echo of Iroh's battle with her father's air squadron, Unalaq's twins managed to work together to force Asami's plane into a crash landing. Though she, Mako, and Bolin had fought as hard as they could once they hit the ground, without the advantage of being in the air they were quickly captured.
The encampment receded behind her as Asami flew through the pass in the mountains that led back to the city. She glanced back, but it appeared that none of the spirits had followed her. They must be focused on protecting the portal. She added that to her list of good news. It was woefully short.
She turned back to the bison and gave him a cautious pat with her closed fist. It turned out that, lack of safety precautions aside, Oogi wasn't all that difficult to pilot. A light pull on the reins attached to his horns and he went higher; slacken them and he went lower. She was reminded forcibly of Iroh's description of flying a plane. There's a stick in the middle, and you pull it one way for up and the other for down. She took a deep breath. He was probably fine.
She'd seen no sign of Iroh during their raid. The burned tents near the decommissioned mecha tanks could have been the work of a firebender, but Asami had no idea why Iroh would burn a few tents and nothing else. But it wasn't like him to not be thorough, especially after he'd risked so much to come to the South Pole in the first place. She didn't think he had been captured though. When Asami, Mako, and Bolin had joined Korra, Tenzin, and Kya as Unalaq's prisoners, Chief Tonraq had been the only other captive. Perhaps Iroh had been interrupted somehow, and had gone somewhere else to regroup? Asami didn't let herself think of the other possibility. Fear gnawed at her stomach.
Luckily for them, Tenzin's brother Bumi had somehow avoided capture. He managed to free the group, including a badly injured Tonraq, and give them a few minutes to regroup. Asami, as both a pilot and a non-bender whose talents would be less useful in a rematch with Unalaq, had agreed to use Oogi to fly Tonraq back to Katara's where she would be able to heal the worst of his injuries. Meanwhile, the rest of the team would attempt to gain the portal and seal it. Asami had been flying ever since.
The lights of the city grew closer as she flew through the night. A sky bison was not exactly inconspicuous, but with the majority of the Northern Water Tribe's forces engaged either at the portal or to the east of the city, she wasn't worried about being spotted. Unalaq would be concerned with anyone moving towards the portal, not away from it.
Asami had the bison land in the street outside Katara's house. Almost as tall and wide a house himself, he barely fit. She looked back at Chief Tonraq in the saddle basket. His face was pale and drawn, and he'd pulled the thick woolen blanket covering him tight up under his chin. He was a big man, and heavily muscled. She didn't know how well he could walk, but she'd never be able to carry him down off of Oogi's back alone. Perhaps Katara would have some other method of moving him.
Asami slid down Oogi's side. It was a bit of a drop, and she landed in a crouch. Her boots crunched in the snow. Then she pelted up the narrow walkway and pounded on Katara's door.