Vigil Weatherwatch finally made it into the city of Canterlot to continue his research for revolutionizing weather management. With the magic that the unicorns could provide there, he could change Equestria for the better.

But when the Changelings invaded, it was there too that he saw how small his dream was.

Though the Changelings were repelled and the damage to the city has been mended, the images a fallen Princess Celestia and the powerless Elements of Harmony still left everypony in fear.

Unrest spreads once again when a squad of Wonderbolts go missing over the Everfree Forest. Believing to do what's necessary, Vigil has to be prepared to live through the consquences of becoming a Guardian, learn the powers of the Armament… and find out what mysteries the forest holds.