Writing a fantasy novella. A primary inspiration is the chronicles of Narnia but I'm struggling to decide how my characters get from our world to the fantasy realm. My basic idea is that a epic battle taking place in the fantasy realm makes reality unstable. I want my characters (who are teens not children) to accidentally end up there not be taken there to fulfill prophecy like the Pevensies.
Like how they actions they go through to get there, or the metaphysical theories behind how that works? Because, IMO, the latter is not really important, so long as it doesn't break a readers suspension of disbelief (which has a much higher bar in Fantasy), and for the former, you just need some kind of portal or threshold for them to cross. Not knowing your setting, though, I couldn't say what would be apropos though it could be practically anything.. It could be a lightening storm, a tunnel under a train station, or a vortex summoned by the necronomicon.
My characters are teens (around 15) all friends going to school together in modern day London. One girl, two boys. My main problem is how they get to the portal (or whatever it is) I was thinking they were out together at night and come across it. Another idea I had was a ancient magic portal they accidentally activate during a school trip to the museum. I really want them to end up in the fantasy world accidentally.
It would be in bad taste to suggest a near-fatal opioid overdose took them there, wouldn't it? Or maybe a traffic accident? Kind of depends on what kind of kids they are. And they won't regain consciousness until they triumph in fantasy land? And will die if they don't do it soon? And they're told that, by a person in fantasy land of dubious credibility. Or maybe they're playing a board/video game ... (jumanji) So many tropes, so few pages ...
The portal is in a place of great import in both worlds - a hilltop. In the fantasy world, the major opponents have scheduled a formal war on an auspicious date and time to settle a feud of ownership over some important trinket. Meanwhile, da kids are visiting some slightly out of the way spot in Eastern Europe. There is a local festival on a hilltop near town celebrating an obscure old seasonal rite that no one remembers what it was about. The "Journey Hill". As the young-uns do the ribbon dance or whatever, the armies collide in fanta-land and the super trinket is accidentally destroyed, sucking the hilltop into the fantasy world. Trinket is gone, portal effectively gone, formal war ends in failure, world crisis begins, children suspected of being both the cause and solution to fixing the trinket. Go!
Or a series of standing stones or an ancient grotto that looks like a good place to go and get blotto.
Or that bathroom at the gas station that the guy at the cash register can never seem to find the key for. It's "ever so mysterious."
When you said "accidentally" end up there, my mind immediately went through tripping headfirst into a portal, which wouldn't be as feasible for a group unless they were all tied to one another like spelunkers. But what about a car accident? Driver loses control with everyone in the car, crashes straight into a wall—only they go through the wall and into Not!Narnia.
Or maybe they board a "Not in Service" train in the tube, just for fun. Then an odd conductor enters the car they're in, says "You shouldn't be here," and suddenly there's green fields and lush forests visible through the windows, and they're not in London anymore. Kind of depends on how routine it is for "certain people" to travel between the worlds. Must be pretty common, if they have a train in the Tube for doing it.
We have a place near my home known as 'The Fairy Rings', which is basically the worlds smallest Stonehenge- (stupid name I know but its true). Anyway, kids often go there to either smoke a bit of weed or for a night of adventure telling ghost stories and scaring each other. What if, on one particular night in each generation, something magical happens and draws them into a fantasy world...
We used to break into an abandoned water tower. It was very portal-y, squeezing through the inspection hatch and stumbling through ash, dust, sediment, and broken beer bottles while waiting for your eyes to adjust so you could get to work on the camp fire.
Hmm...epic battle in fantasy realm. OK, so that, to me, puts the teens in a field or other open space (to mimic the battlefield in the fantasy realm). Perhaps they are at a park for a picnic. They start to argue. Maybe the two boys start shoving each other and the girl tries to break it up. The combination of the two similar events (fantasy battle and the argument in our reality) makes the veil between the two worlds even more unstable, and suddenly the teens slip through and find themselves in the middle of a fantasy battlefield. What do they do now? How do they avoid getting killed? Aaandd...go.