Bettie/Tonshi and Buster had made it all the way down past the first falls now in their inner tubes. It was not Wednesday but it was time. Timmy Time.
They stood up. “What now my love?”
Buster told her his plan as the inner tubes vanished, one then another. “Follow me.”
—–
“Hold on Tonshi!” he called through the floor.
“I will!”
—–
In.
Sunklands 
That’s excellent underground camera work and clever use of an Ickle!