The strange apartment in the mountains

A few years ago, my friends and I rented a small apartment during a summer trip near the mountains. Everything seemed normal during the first two days, but strange things slowly started happening afterward. One evening, we returned from dinner and discovered that the kitchen light was already on even though nobody remembered leaving it on before we left. At first, we laughed and blamed each other. Later that night, while we were watching a movie, we suddenly heard loud footsteps coming from the floor above us. The problem was that the apartment owner had told us nobody was staying upstairs. Around midnight, the electricity briefly stopped working for a few seconds. One of my friends became so nervous that he refused to sleep alone and moved his mattress into the living room. The next morning, we discovered the truth. A group of travelers had accidentally entered the empty apartment above ours late at night because they had received the wrong keys from the owner. After that, the whole situation became much funnier than scary.