EDIT : SWAP OHM NANON WITH SEA JIMMY

I Saw a lot of people commenting they don't get the trailer at all. i don't much either, but i have a theory i just wanna put down here :

Apply Stephen hawking's theory of multiple universes:
Ohm's and Nanon's characters died in their universe but let's assume their bodies  weren't found.
their consciousness gets transferred to talay and tun.
either talay and tun's consciousness is dead or is locked away or is transferred to the body of ohm's and nanon's in their universe. an inter-dimensional soul swap game .

now as we can assume from the trailer, ohm and nanon in talay and tun's body get to know they both swapped and eventually fall in love. ohm wants to return and nanon doesn't. i guess nanon later on does too.

the lady who told ohm to find nanon ,and they are the portal keys , that lady is probably someone like "doctor who " works from time line to time space making sure of things. And she gave ohm the advice to find his portal key if he wants to go back to his universe and body.

now assuming they can go back to their own bodies in their universe with the help of portal keys ( aka lovers i guess lol  or soulmates) that means their physical body is alive,  either unconscious or taken over by talay and tun's consciousness.

now this is just my theory nothing for sure . havent read the novel, dont even know if there's one