They say you don’t really know someone until you live with them. I thought I knew my mother-in-law well, but everything changed the day I decided to follow her. What I discovered wasn’t just a secret — it was a ticking time bomb threatening the peace of our home.

Before, my days followed a predictable rhythm. As a freelance graphic designer, I worked from home, enjoying a flexible schedule and a decent income. My husband Xander spent most of his time at a prestigious law firm, often leaving me alone in a nearly idyllic calm… until, three months ago, my mother-in-law Cordelia moved in with us.

One evening, after her husband died, she called us with a trembling voice: “Olivia, my dear… I don’t know how I’ll manage alone. The house is so empty, so desolate… I need my family close to me.” My husband and I agreed, thinking it was the right thing to do for a woman who had just lost her partner of 40 years. But very quickly, her behavior became strange.

Every Thursday morning, Cordelia would leave the house and not return until late in the evening — and each time, she reeked of a foul, damp odor, reminiscent of rot. The stench lingered long after she came home, and I couldn’t stop wondering what she was really doing.

One evening, Xander asked her in a calm tone, “Mom, where were you today?” She avoided our gaze and replied, “Oh, I was meeting some old friends.” Her answer rang hollow. “Every Thursday?” I pressed. She shrugged, “It feels good to see old friends again.” I remained convinced it wasn’t just a simple get-together. My curiosity grew.

The next Thursday, I pretended to be sick and followed her from a distance. She wrapped herself in a large coat, grabbed her bag, and disappeared down a narrow alley I didn’t recognize. My heart pounded. At the end of the street, she entered a dilapidated old building with boarded-up windows and graffiti-covered walls. Despite my fear, I followed her inside.

The air inside reeked of stale air and cigarette smoke. Low voices and occasional laughter echoed. What I saw horrified me: an illegal casino, with flickering lights and the clinking of poker chips. And in the center of the room — Cordelia, eyes blank, her gaze fixed on her cards, hands trembling as she bet and lost. She looked possessed, as if by an inner demon. I wanted to call out to her, but I was frozen.

When she finally left late that night, she walked slowly, exhausted, her face marked by defeat. The next morning at breakfast, I snapped: “Cordelia, where were you really last night?” I said, slamming my cup. She barely looked up: “With friends.” “Stop lying,” I shot back sharply. “I followed you. I know you were in an illegal casino.”

Her tears poured out. “I… I lost everything. I didn’t know how to tell you…” Behind her, Xander finally understood the truth.

From that moment on, there was no turning back — we had to decide what to do next, for the good of everyone.