Max M. answered 04/23/21
Improve your skills and scores with a Harvard grad.
Hi Catherine,
You're off to a great start! A message from a stranger could be a very cool Call to Adventure. But if you're not sure if it's your best bet, one thing that can be helpful is to think backwards. What is your hero going to achieve (or fail to achieve)? Then you can think of how she does it, and then what she needs to do to prepare, and then how she learns about the quest in the first place.
For instance, let's say she slays the dragon that's been devouring helpless knights. Maybe she does that by assembling a magic spear, which has had its pieces distributed in four different kingdoms. To do that, she needs to learn the location of each one, travel to impossible places, and solve the puzzles and traps that guard them. She could learn about the first one when she moves to a new town and doesn't understand why her new friends won't go near the Forbidden Cave. In this case, the friend's warning about the cave is the Call to Adventure.
I know this was a pretty generic example, but the important point was that sometimes it's easier to think backwards than forwards. Again, a message from a stranger could definitely be a great call to adventure, and you certainly *can* just make it up as you go along, but if you're hesitating, try thinking of what your best ending is and build it from there.