He  heard Kestrelflight break in with a heated objection, but he couldn’t go on listening, because the pressure in his head was building up until he couldn’t bear it anymore. The tingling in his body intensified. He forced his head back to gaze upward; the sky was still dark and starless, but when he closed his eyes, a  series  of  bright  images  began  to  flash  through  his  mind:  one  cat  after another, as clear as if they were standing right in front of him.
As images of Twigbranch and Lionblaze flashed before him, a voice echoed inside Shadowpaw’s head. “The Clans have forgotten the code,” the voice whispered. “It has been broken time and time again, and because of the codebreakers, every Clan must pay a price. They must suffer.”
The images continued to flash through Shadowpaw’s mind, faster than before. He saw Crowfeather, Squirrelflight, Mothwing, Tree, Jayfeather...Each  face  tightened  Shadowpaw’s  chest  and  made  it  harder  for  him  to breathe, until one image stopped his breath completely.
Dovewing?
His mother’s face loomed large in Shadowpaw’s mind, but he couldn’t understand  why  she  was  being  shown  to  him. She  can’t  be  one  of  the codebreakers—can she?
As swiftly as the images had come, they were gone, and Shadowpaw became aware of Puddleshine prodding him in the side. “Shadowpaw, are you listening?” his mentor demanded. Shadowpaw shook his pelt, trying to pull himself together quickly so that none of the other cats would realize that he had just had a vision.

Lost Stars, Chapter 13