Oh dear. Oh no.
It looks like in this post-apocalypse Shouta and Clementine are the only humans left on earth as far as they know, trapped on a remote island with lush vegetation, and no one else, zombies or otherwise.

How will they keep humanity from going extinct?
How, I ask you

https://www.youtube.com/watch?v=RihCkopGGQs&t=12s

https://files.catbox.moe/97wt5a.jpg

https://files.catbox.moe/25mx9j.jpg