On August 2nd, I parked my car in the garage. It was deserted. Upon reaching the building's front door, I opened it to curse again about a problem with the elevator, which was beautiful and old, but very impractical. I live on the sixth floor of a seven-story building, so I began my climb resignedly. On the third floor, I tripped over something, and when I turned on the light in the landing, I saw a large set of keys lying there. It's midsummer, Madrid is almost empty, and I'm a journalist with time on my hands and a curious nature. Keys are used to open doors, mailboxes, cars, dreams, and even other people's lives. Yet, you don't expect to encounter a love story and a mysterious death that inevitably demand investigation. The lives of others can be quite surprising.