Actually play with me in this space - what if this reality is similar enough to theirs that it has a Martin and a Jon of its own?
They have normal jobs and don't know one another. Maybe they both have some mild interest in the paranormal. Nothing passionate, just enough to occasionally scroll through blogs over breakfast.
Both of them come across an article about two mysterious corpses, which includes photos and transcripts of what little audio was recovered. Some of the audio mentions their names. In two different apartments across London, two men who've never met do simultaneous spit takes.
Both look up any information they can find. A paranormal podcast gets a hold of some audio files from the recovered tapes -- and holy shit, one of the voices even sounds like them.
Most of the tapes are too damaged to recover so there are only tiny fragments of the story we, the audience know. Enough to get a sense of a few small things -- a few other names, a disturbing experience or two. A warning of something terrible coming.
(Maybe, maybe, just the faintest hint of a love story.)
Neither knows what to think or how to feel. Both throw together theories in their minds -- alternate dimensions, time travel, bizarre coincidences with identical strangers.
Jon becomes obsessed, hunts down any scrap of information out there and pieces together wild theories. Martin mostly goes on with his life, but finds himself frequently wondering who those people were and what happened to them, now and then doing some googling in case something new has been unearthed.
The news cycle leaves the story behind as a mildly weird dead end. Paranormal blogs move on to other things. Months pass.
One day there's a tiny, rinky-dink paranormal convention in London. Neither of them would have any interest in it, except one of the panels promises to play a new section of recovered audio from the "Harbinger Tapes," never before heard by the public.
They see each other outside the convention center and lock eyes.
Both of them have seen photos of the mystery bodies, and those faces are burned into their retinas. For a long minute, both of them stare in shock. Jon's the one who finally breaks the silence and approaches.
"Hello," he says, smiling awkwardly. "I, ah. I think I was found dead beside you in a London alleyway last March?"