Signed, Sealed, Delivered: Lost Without You (2016)
You just knew giving the kid the package to post was a bad idea but the state he got it in was looked like it had been around the world a couple of times and them posting in a mailbox that was used as a prop I thought was a stroke of luck, the fact they spent a week trying to find who sent it made a change as this was starting to look like the one they couldn't deliver. Oliver and his father getting into trouble on their camping trip could of been fatal but using the dog the letter was for to find them was awesome