" What are you doing here?” he mumbled.
“Um, you asked me to follow you?” Marrill said. The wizard chuckled. “Not you,” he said, continuing downward. “I meant the Promenade Deck.” He waved his hand over his shoulder at the floor they’d just passed. “You’ll have to watch out for that one—it likes to walk off. Best to stay away from it. Never know where it’ll end up; sometimes it up and heads to another ship.”
“Um…” Her words faltered. “How do I know which one’s the Promenade Deck?” He glanced up at her, forehead furrowed. “It’s the one that moves. "

― Carrie Ryan , The Map to Everywhere (The Map to Everywhere, #1)