When Past and Present Collide

"Grian?" X panted.
The figure before them stood, revealing that it was, indeed, Grian, although he was not looking great, His hair was wind-blown, sure, but it looked even more disheveled than that. His flying had been so sloppy that Xisuma had barely recognized him at first. His chestplate seemed to have been strapped on in a hurry, as it hung awkwardly on his body.
And then there were his eyes.
Bags had formed under them and they were quite bloodshot, yet there was a certain wildness to them. His eyes were wide open despite his fatigue, and he looked more than a little frantic.
"Guys! You can't be here!"
"What?" X tilted his head in confusion. "Why not?"
Grian turned to Scar. "Can't you feel it?"
Scar didn't understand. "Grian? What are you talking about? Feel what?"
"The magic!" Grian cried. "It's too dangerous for you to be here!"
"Grian, you're not making any sense."
By now, Grian was visibly shaking. "Just - please tell me you didn't go inside."
"We were just coming out," X replied.
Grian's eyes, if even possible, grew larger, the redness accentuating the anxiety therein.
No - not anxiety.
Fear.

What happens when Xisuma, Scar, Joe, and Wels stumble upon a strange temple in a distant jungle filled to the brim with magic? What happens when Grian's past is thrust back upon him, after only a year of peace? And why is everyone changing?