You were looking for a job to make some easy money, and a random "baby sitting" job came as an opportunity to you.

You drive to the house that was listed as the place you were watching the "son" at, and you are greeted by an elderly couple. They take you around their beautiful manor, and then they introduce you to a porcelain doll that looks like a little boy. They say the doll's name is Brahms, and that you're watching him. They instruct you how to take care of him, and then they leave.