*****R18+****

　　Elena's POV.

　　We got to the training center, "Elena, Derek called out, and my heart beat faster. I raised my head up to see him, his face was neutral, and I gave him a smile.

　　"Sir," I responded, my voice clear.

　　"I don't quite understand this," he said, passing me my book. "Meet me at my office to explain," he added in a firm voice, and I nodded, swallowing hard.

　　I took my book from him, and he walked away, leaving ...