As the distortion of space faded and his feet touched solid ground, a damp, chilling air washed over him. Sasuke Uchiha found himself in a broad but dim metal corridor. Overhead, luminous ores embedded in the vaulted ceiling cast a pallid light, while cold walls covered in pipes and runes lined either side. The air carried a faint scent of rust and a sense of... subtle chakra surveillance that seemed to be everywhere.
So this was the Akatsuki's base? Hidden somewhere in the Land of Rain.
"Welcome to one of my temporary hideouts." Tobi's (Obito's) voice sounded beside him. He had already returned to his slightly flippant tone, as though the solemn figure who had called himself "Madara Uchiha" moments earlier had been an illusion. "Come with me. I'll find you a place to stay, and then... we'll begin our 'lessons.'"
He led Sasuke through the labyrinthine corridors. They encountered no one along the way, only the occasional low hum of unidentified machinery from deep within the walls. At last, they stopped before an unmarked metal door. Tobi casually formed a hand seal, and the door slid open without a sound, revealing a room so sparsely furnished it was almost empty. There was only a stone bed and a crude washstand.
"It's nothing fancy, but you'll have to make do." Tobi gestured toward the room. "Here, you won't have to worry about Konoha's flies for a while. Of course, don't go wandering around either. Some places... aren't very safe."
Sasuke paid no attention to the accommodations. Power concerned him far more. "When do these 'lessons' you mentioned begin?"
"Don't be so impatient, Sasuke-kun." Tobi spread his hands. "First, let me see just how bad your current 'foundation' is. Release your chakra. Let me see how you're getting along with that