Sekai no Owari no Pen-friend

Kasumi Arai was only six years old when the world plunged into chaos: earthquakes emerged, diseases spread like wildfire, and society began to crumble in the clutches of an eternal winter. Her only solace in the present is an old, abandoned stationery store that withstood the test of time amidst the disorder of the world. While there, she often uses a vast array of colorful pens to draw her favorite anime character, Miracle Momo, just to pass time.

After reminiscing with his friend about the days before the end of the world, a young man decides to make a trip back to his family's stationery store and discovers Kasumi's drawing within. Feeling nostalgic, the man sketches the same anime character, triggering a correspondence between the two unlikely individuals.