30 Days 'til the World Ends

On a peaceful day, a text message announces the countdown until the end of the world. Soo Ah, a cheerful high school girl, sees how all of her loved ones gradually disappear and panics. She decides that the last thing she can try to do is save Sun Woo, her dear friend and crush.

(Source: Webcomics)

Note: Chapter count includes a prologue.