The nanny found out why 6-year-old Leo screamed every night.Every night at exactly 2:13 AM.My name is Clara. I’m 26, and I’ve been Leo’s nanny for eight months. The Millers hired me because no other nanny lasted more than two weeks.”Leo has night terrors,” his mother, Mrs. Evelyn Miller, told me on my first day. “He’s a very difficult sleeper. Don’t worry about it.”But it wasn’t night terrors.Every night, Leo would go to bed fine. Then at 2:13 AM, he would start screaming like someone was hurting him. Thrashing, crying, clawing at his head and neck. His parents would lock their bedroom door and tell me to “let him self-soothe.”Last Tuesday, I couldn’t take it anymore. I ran into his room, picked him up, and he was burning hot, sweaty, whispering, “It hurts, Clara. My head hurts. It buzzes.”I laid him on the floor, away from his bed, and within 10 minutes he stopped crying and fell asleep peacefully on the rug.It wasn’t a nightmare. It was the bed.The next day while Leo was at school, I went into his room. I checked everything. His mattress was brand new, organic, $2,000 his mother bragged. His blanket, his sheets, nothing.Then I picked up his pillow. That expensive, “orthopedic, memory-foam, imported from Germany” pillow Mrs. Miller insisted he use and no other.It was heavier than it should have been.I unzipped the cover. Inside the foam, I felt something hard. I ripped it open.Inside was a small black device, about the size of a coin, with a tiny blinking red light. It was sewn into the center of the pillow and it was warm to the touch. It was vibrating faintly.It wasn’t a tracker. It was an ultrasonic emitter.I don’t know where Mrs. Miller got it, but I Googled the model number on the back. It’s a device used to deter animals — it emits a high-frequency pulse that causes headaches, nausea, and extreme sleep disruption in small children. Adults can barely hear it, but to a 6-year-old lying right on top of it, it’s torture.Why would a mother do that to her own son?I removed it, threw the pillow in the trash, and took Leo to my room that night. I put him in my bed with a normal pillow.For the first time in eight months, Leo slept through the night. No screaming. No 2:13 AM horror. He woke up smiling.”Clara, I didn’t have the bad buzz dream,” he said.I hugged him and said, “You never will again.”I kept the device in a ziplock bag.Because by morning, I wasn’t just going to quit. I was going to show that device to Mr. Miller, and if he didn’t believe me, to Leo’s pediatrician and to child services.Some family secrets aren’t meant to stay hidden.