Cassie 

A girl who survives the world's apocalypse, Cassie, wanders around a collapsed city alone.  As she was walking along the collapsed building, she heard sounds and felt curious if there was any human being other than her still alive.   She lifts some rocks to clear her way to find where the sound is coming from. Then she found a kitten under the collapsed building. She rescued it and brought it to her shelter.  she took care of the kitten till it grown up. She named the cat Garfield. They both become best friends. Garfield getting clingier to Cassie and go through a lot of adventure. Hunting for food from city to another city, sometime in the forest nearby. Build up shelter at different city as they go get new supplies to keep on living. As they counting days, on one evening, Cassie sit on top of the hill watching sunset and a huge mushroom shaped smoke can be seen on the sky as Cassie tearing up hugging Garfield. As the world caves in.