I don't own any canon characters.
Simba was decidedly uneasy the next morning. The plan they'd eventually formulated the day before was to draw Zira's pride out into the open, then Kovu would confront them. The problem was, Zira would only come into the open if Simba was dead or injured, and since dead wasn't an option, he would have to appear to them to be injured.
This meant that both parts of the plan relied almost entirely upon Kovu's loyalty and timing, and while timing wasn't a worry, Simba, still wasn't entirely sure he could trust the young lion.
Kovu himself had left before sunrise to inform the Outlander pride to prepare an ambush to lead Simba into. Once they had been ambushed, he would accuse the younger lion of being a traitor, and attack him. During the resulting fight, the younger lion would then fake a momentary disadvantage, giving him time to escape.
After Simba escaped, injured, Zira would probably attack anyway, and if she didn't Kovu would do his best to persuade her to. He would then return to the Pridelands, and when the prides faced off to fight, he would try to resolve the situation without violence. At least, this was how the plan was supposed to go.
Soon enough, Kovu returned, and said, "they should be ready in an hour or so."
"Good," Simba said, managing to hide his unease. "This is it then," he muttered to himself.
Nala came up to him, nuzzled him, and said so that only he could hear, "don't worry you'll be fine."
"I only wish I could be fully sure, "Simba replied quietly, "there's just a hint of something I don't trust in Kovu."
"A bit late to back out now, though," Nala said.
"Yeah," Simba said, and prepared to leave.
Meanwhile, Kiara went up to Kovu, and said, "I don't like what you're doing, it's too dangerous."
"Not for me," Kovu replied, "it will be for Simba though."
"But it is dangerous for you," Kiara insisted, "what if they find out about this?"
"They won't find out," Kovu said, "I promise."
"Ready to go," Simba asked.
"Yeah, uh, just coming," Kovu said, then gave Kiara a quick nuzzle, "bye."
"Bye," Kiara called, as Simba and Kovu descended Pride Rock. Turning to Nala, she said, a little worriedly, "I hope they'll be alright."
"I'm sure they will," Nala replied, "although Simba still doesn't entirely trust Kovu."
"What," Kiara asked, slightly astonished, "but Kovu..."
"I know," Nala said, consolatory, "but your father is harder to sway."
"But why," Kiara asked, "I mean, Kovu's entirely loyal."
"I know," Nala replied, "but for years, your father blamed himself for the death of his own father."
"Oh," Kiara said, taken aback, "I, why didn't he ever tell me?"
"He wanted to protect you from it," Nala replied.
"That's terrible," Kiara said, then rallied, "but what does it have to do with Kovu?"
"Kovu was trained by Zira," Nala replied, "Zira was Scar's senior mate, and she loved him."
"I still don't see how..." Kiara began to say.
"Hush, Kiara," Nala said, then continued, "Zira was better to us than Scar, but when Simba was forced to kill him, she became evil."
"I don't..." Kiara began again, then realised, "...oh."
"Yes," Nala said, "Simba tried his best to help Zira, but she wouldn't accept help."
"Why not," Kiara asked.
"She'd loved Scar," Nala replied, "when Simba was forced to kill Scar, she hated him for it, hated him enough to try to kill him." Her voice took a sad tone, as she went on, "none of us really wanted to exile her, but after what she did, it was necessary."
Kiara was speechless, shocked. "Why," she asked, after a few seconds, "why didn't anyone tell me?"
"Simba thought you'd be safer if you didn't know," Nala said, "he was only trying to keep you safe." Kiara wasn't sure what to say to this, so she kept quiet.
Simba and Kovu left Pride Rock in silence. After some time, and some thinking, the elder lion asked, "where's the ambush laid?"
"It isn't actually laid yet," Kovu replied.
"Why not," Simba asked.
"I couldn't be sure where we were going to go," Kovu replied, "so I had to get Vitani to watch us."
"Vitani being one of the lionesses," Simba asked.
"Actually, she's my sister," Kovu said, "she's one of the best stalkers in the Pride."
"So you don't actually know where or when the ambush is coming," Simba asked, concerned.
"It won't be too far from the Outlands," Kovu replied, "but, yes, I don't actually know."
Simba though about what Kovu had just said. "I wish you'd told me earlier," he said.
"There wasn't that much time if I remember," Kovu replied, hoping Simba wouldn't take it the wrong way.
"Well, no matter," Simba said.
Kovu spent a moment wondering if Simba was angry, before the king went on, "there was something I was going to show you yesterday, something that may apply even more now."
"Sire," Kovu asked, perplexed, but Simba didn't reply, so he followed the king. Neither of them talked, as they neared the border.
When they reached the burned patch, where the sparks from the fire had reached across from the Outlands to the Pridelands, and started up again, Simba called a halt. "what do you see here Kovu," he asked.
"Erm," Kovu looked around, before replying, "it looks dead, sire."
"Indeed it does," Simba said, "and fire, undeniably, is a killer. But," he went on, stamping suddenly, "sometimes, what's left behind can grow better than the generation before..." He bent down, which Kovu followed, then removed his paw to reveal the start of a small green shoot emerging from the ash, "...if given the chance."
"And sometimes not," said a voice behind them, followed by chuckling.
Both Simba and Kovu rose and looked at where the voice had come from. Zira appeared, flanked closely by Vitani and Nuka, and the other lionesses had spread themselves out in a ring, encircling the pair of lions.
"Zira," Simba said coldly.
"Why Simba," Zira said, still chuckling, "what are you doing out here, so, alone."
"Kovu," Simba growled, turning to the younger lion.
"Exactly to plan," Kovu chuckled. Simba wondered for a moment if the younger lion had turned on him for real, but the expression of his eyes denied it.
"Traitor," Simba said, his voice somewhere between a growl and a roar. He then leapt at Kovu, and the two began to fight, though both pulled the blows slightly, and their claws were only half-extended.
The moment the fight started, Zira barked a command, and the pride stopped advancing, but stood ready for action in case either one of the lions looked to be getting the upper hand. The queen herself couldn't have been more pleased with the result. She'd wondered what had happened to Kovu the day before, as a result of Vitani's report, but now her confidence in the young lion was fully restored.