Amber closed her eyes, sighed, then calmly looked back at her son.
"That stone," she began, "is shrouded in a great deal of mystery. However, just as there is a lot of mystery behind it, there is also a lot that is known about that stone. As I told you before, the stone in your arms is the Dark Stone. A good way to describe what that stone is…" She paused to collect her thoughts. "The Dark Stone is a physical manifestation of Zekrom's power, a dormant form of his essence; in other words, the Dark Stone is Zekrom's spirit."
"That's amazing," Luke whispered, looking down at the stone in his arms.
"Yes, it is," Amber mused. "In any case, as long as the Dark Stone is kept safe, Zekrom will endure. In that regard, Zekrom isn't truly dead; he's merely resting. The Dark Stone is a form that Zekrom assumes only in extreme circumstances, such as when he has sustained severe physical damage; your battle against Reshiram is one such case. Zekrom used all of his power in that fight, and sustained a staggering amount of injury and fatigue along the way."
"Yeah… We didn't stand a chance," Luke lamented.
Amber shook her head sadly. "The situation was out of your control, son. Reshiram is already a very powerful Pokémon, but due to the emotions within her heart, her powers have been magnified. You and Zekrom fought bravely with everything you had. You did the best you could do, Luke. Trust me, with what I'm telling you, you'll be back on track before you know it." Luke managed a smile at his mother's words of encouragement, remembering all the times his father had given him a similar pep talk. After Amber had finished cheering up her son, she continued her explanation.
"In the same vein as Zekrom, Reshiram changes form as well: when the situation calls for it, like what happened to Zekrom, she becomes the Light Stone. Just as the Dark Stone is the dormant form of Zekrom's power, the Light Stone is the same for Reshiram."
"So, what then? What exactly do these stones do?" Luke asked.
Amber clarified her prior statement. "On their own, the two stones do nothing. However, when exposed to the right conditions, the stones can be restored. Basically, if you know where to go, the powers of Reshiram and Zekrom can be restored, thus reviving the dragons from their respective stones."
Luke's curiosity was now peaked; he couldn't help but wonder how his mother knew so much about these two stones, but he was greatly relieved to have some insight on his current predicament, feeling more and more optimistic along the way.
Sensing her son's curiosity, Amber spoke again. "I know your wondering about this convenient wealth of knowledge of mine," she said with a smile. "While living back at the agency, I've learned a great deal from stories I've heard from travelers and the various rescue teams and things I've read in the library."
A light went on in Luke's head at his mother's last statement. "About that," he chimed in, "back in the library, I came across this particular book. On the cover, there was a sort of design of Reshiram and Zekrom, almost like a kind of emblem. The book had a lot of information about the two dragons, such as where their shrines were located, the ancient war that led to them hiding within those shrines, and a great deal of information about their powers and various special talents they had, namely their respective affinity toward truth and ideals."
"I know what book you're referring to," Amber said, happily. "I've read that book, as well. I've also heard a few things about the two dragons, as I'm sure you have."
Luke nodded. "Yeah, some of the others were at least able to answer some questions about Reshiram. We didn't actually know about Zekrom until I found that book; I was the one who volunteered to go find Zekrom, since we had concluded from the text in the book that he was the only one who could stand a chance against Reshiram."
Luke immediately fell silent after making that particular recollection. Suddenly, the regret he felt at that particular moment had returned. Quickly, he turned away, hoping his mother wouldn't notice the tears welling up in his eyes.
Amber, however, knew that gesture well. Just as with any mother, Amber could sense her son's distress. Silently, she stepped over and calmly put an arm around him.
Pulling Luke close and lowering her voice to a whisper, Amber gently comforted her son. "Hey, cheer up, Luke. Whatever you may have said or did… I'm sure it was for the best. You're never alone, son; you have your fellow rescuers cheering you on, along with countless other Pokémon all over the various regions of the world. Never forget that, and never doubt your own abilities."
After drying his eyes, Luke was able to speak again. "Thanks, Mom, I needed that."
"Any time, son," Amber said with a smile.
With the incident in the library behind him, Luke thoughts returned to the task at hand. "So, what are these circumstances you mentioned for restoring the Dark Stone? Where exactly am I supposed to take this thing?" Luke was already feeling better after learning that his friend could be revived, as the tone of his voice would indicate.
"That's an easy question to answer," Amber replied, calmly. "With the Dark Stone in hand, you must deliver that stone to another Legendary Dragon-type Pokémon."
"Who?" Luke asked.
"In order to restore the Dark Stone's power, you must present it to the Dragon of Ice, Kyurem," Amber answered.