As the Sun dips behind the clouds, she realises it could be the last time she ever sees it. It could be gone forever, lost in the immense darkness of space and time.
She imagines the world without its beloved sun; no more plants, animals and after a while, humans. Chaos would eat up the world. Few would live long. Many would turn into the zombie like humans you see in horror movies. Sleep deprived and starved cannibals roaming the earth.
The cloud finally moves aside, but not unlike the vision the girl had, there is no Sun waiting on the other side.