SOLVED. Children's/ YA SciFi: twins, elements, swimming, everyone disappeared. [s]

[j]

There are a set of twins for each of the elements. The main characters (boy and girl, probably 10-13 yrs) are the water sign. They live in a beach town and go out swimming one morning, end up in an underwater cave, there’s a loud frequency or bang?? Some kind of forceful disturbance happens. Once they leave and make their way back home they realise everyone's gone, their parents are missing etc.

Unlike other YA’s of a similar plot, I think EVERYONE vanished, not just adults/people over 15.

The twins of the other elements are all across the world and somehow they all come together? I think the wind twins are from England or the Middle East?? They could blow forceful winds.

The book is not the Michael Grant Gone series. I think the book cover was mainly blue. It was probably apart of a series but I’m not 100%. Read it in Australia and in 2011-2013.

Any suggestions are appreciated!! Please please help!!!

[Rainbowheart]

The Day the World Ended

[j]

Rainbowheart wrote: "The Day the World Ended"

YES!!! That's it!! Thank you so so much oh my god.

[Rainbowheart]

You're super welcome, glad to help out!