These, my friends, are very trite and lazy plot devices that readers can see from miles away.
Bottom line: it’s lame and here’s why.
First and foremost, no one dreams like that. Seriously, when was the last time you had a coherent dream with a discernable message warning you of danger. Even self-professed psychics don’t have full-blown storylines during REM. I’m not a psych major, but I have a Ph.D in naps. From my experience, dreams are fragmented images, a psychedelic quilt of the day’s events, old memories, and deep-seeded phobias. There are those rare occasions where a vision will emerge that inspire you to achieve something, some subliminal message that fuels you to act. (Yes, I saw Inception) But 90% of the time, the images resemble acid trips or the result of eating a meatball sub before bed. And it always tickles me when people try to decipher the gibberish to find their destiny.
For example, here was my dream last night. It’s pretty long, but I’ll give you the highlights.
Two zombies walk into a bar. It’s karaoke night and the singer is that redhead guy from CSI-Miami. There is no roof, but twinkling stars and a red moon. For some reason, my mom is behind the bar pouring a row of drinks and nagging me to quit smoking. The zombies agree and ask for my phone number. A fight breaks out, the zombies attack, and all I care about is keeping the karaoke machine working for the next singer to go on stage. True story.
Mind you, that’s all I could remember/ascertain from the dream, because it’s just nonsense, unrelated crap swirling around the toilet bowl of my subconscious. But It proves my point. Dreams don’t operate in a linear fashion or in a way that makes sense.
I recommend you scrap the dream scene altogether, but if you must, MUST have one, make it convoluted enough to be believable. Make the reader work for it. It’s a lazy attempt to add revelation and elaborate backstory. Allow the backstory to play out through dialogue and the character’s actions. Sprinkle bits of foreshadowing throughout the story— don’t dump it all in one scene. If the whole story is a dream, then give some hint to that in the beginning, and don’t try to make it a surprise ending. Not even veteran writers can pull that one off.
For the most part, dreams aren’t really that prophetic. Unless they’re the ones where you think you’re going to the bathroom and you’re still in bed. That’s a whole other situation. Other than that, just chalk it up as heart burn.