Shiori-san wa Temahima Kakaru Mirai-nin - Vol. 1 Ch. 1

[MangaDex]

 

[TheBigMonk]

Thanks for the chapter!
This one seems interesting, I guess?

 

[OWMWO]

This chapter sparks joy.

 

[Dekker]

Normally I hate time travel. But I guess it's actually pretty fine to kick off a story with

Thanks for the chapter!

 

[blablablub]

Is this some "I'm my own great-great-grandma" kinda thing?

 

[Alex_ZXZ]

Its that simple, huh...

 

[kamykowsky]

Is this Oogami and Makiba?

 

[ARealCoolGuy]

She's totally discounting the possibility of him being one of her ancestors.

Is this some "I'm my own great-great-grandma" kinda thing?

Almost certainly. It would explain why she is disappearing when she moves further away, because that means they're destined fate of giving birth to their own bloodline isn't going to happen.
It could also be something a little more convoluted, like their child saves the life of a woman who is an ancestor of the FMC -- a butterfly flaps it's wings type of scenario.