Niagara Mystery

A family were on summer break and they decided to go to Canada to see the Niagara falls. they had two children a 12 year old Girl named Twilight and a 6 year old Girl who is a brat named Maya! . Once they reached Canada. Maya and Twilight decided to ride the Niagara Falls without their parents. Suddenly the boat sinked and everyone died. Except....... Maya and Twilight. These two went into a different world that was underwater. They were confused " how come the others died? and we didnt? ". After being stuck in this new world they are trying to find a way to go back and find their parents.
But how? Will they succeed? Will these two finially get along?