Every night, my mother-in-law would knock on our bedroom door at 3 a.m., so I set up a hidden camera to see what she was doing. When we saw her, we froze… Liam and I had been married for a little over a year. Our life together, in our quiet Boston home, was peaceful—except for one thing: his mother, Margaret. Every night, at exactly 3 a.m., she would knock on our bedroom door. Not loudly—just three slow, distinct knocks. Knock. Knock. Knock. Just enough to wake me up every time. At first, I thought maybe she needed help or was just a little lost in the dark. But every time I opened the door, the hallway was empty—dimly lit, completely silent. Liam told me not to worry. “Mom’s not sleeping well,” he would say. “He sometimes wanders around a bit at night.” But the more it happened, the more uneasy I felt. After almost a month, I decided to find out the truth. I bought a small camera and discreetly attached it to the top of our bedroom door. I didn’t say anything to Liam—he would have assured me I was exaggerating. That night, the knocking started again. Three soft, muffled taps. I pretended to be asleep, my heart pounding in my chest. The next morning, I started the recording. What I saw chilled me to the bone.