I Babysat the Wrong Family for Half an Hour

I had just moved to a new town and picked up babysitting through an app. My first booking was for a family on Birch Lane, seven in the evening, two kids. The message said the door would be unlocked and to let myself in.

I found the house, tried the door, and it opened. Inside, two kids were watching cartoons. I introduced myself brightly, said their mom had hired me, and got to work. We did a puzzle. I made them the snack the fridge seemed to suggest. They were a little shy but perfectly happy. I texted the parent number to say all was well and got no reply, which I figured meant they were at dinner.

About thirty minutes in, the front door opened and a man and a woman walked in, froze, and stared at the stranger doing a jigsaw with their children. The woman said, very slowly, "Who are you." I said, with total confidence, that I was the babysitter. She said they had not hired a babysitter.