When Star Swirl the Bearded's wicked apprentices Cirrus and Archeon had ended their campaign of looting, murder, and destruction across the worlds Linked to Aitran Island, there were more intact books than were uncovered by Twilight Sparkle and Rainbow Dash. One of those books is I'strukun, the link to the first in a network of worlds intended to instruct Star Swirl's apprentices and daughter in the principles behind Writing links to other worlds. When Nyx insists she be allowed to take the lessons and Star Swirl admits his fear that Cirrus and Archeon may have caused great destruction to the worlds, Twilight and Spike accompany Nyx and take a look around.
Sequel to Aitran and Sohndar