Will to Tasogare no Tabi: Twilight journey to find someone

"I want you to find a woman named Olga who is in the Tree Tower. And if you’re able to find her..." Those were the words that led him to a mysterious place where the sun never sets. A boy named Will, who has no memories, climbs the Tree Tower — to search for Olga, and to discover what it is he himself is truly seeking. At the end of his twilight journey... what will he find?