"Horizon" games universe. "A thousand-year-old Halloween".

To Aloy, these ruins are just another puzzling structure of The Old Ones, filled with the debris of fallen metallic pillars and rusted car frames. Aloy is well-used to the silence of dead cities, but this time, a passing Tallneck disrupts the quiet. As the Tallneck strides by, a powerful surge of its energy overloads an ancient transformer, and a massive dark screen in the center of the square suddenly flickers to life. A miraculously preserved recording lights up the display: a vibrant greeting wishing everyone a Happy Halloween 2064. Aloy freezes before the glowing canvas, completely unaware that this bright billboard was the last thing people saw here right before they had to flee from the first Faro robots. The attack by the Faro robots began in the autumn of 2064, but the government kept this threat hidden from the public. The Old Ones - especially those who lived in remote cities, continued to live their normal lives. And only on November 3, 2064, Operation "Enduring Victory" was announced and that changed people's lives forever.