I Remember a Lot of Octobers

Mara Burke is the last person alive on Earth as the entire world's population has been decimated by a plague. Day in and day out Mara scavenges for supplies and fights to survive. On this particular day she breaks down and decides it's time to end the struggle by taking her own life. She dawns a white dress, grabs a pistol and fills her bathtub with water. Mara sits in the tub, lets out one last cry and puts the gun to her chin. As she's about to pull the trigger, she hears 3 loud knocks. Mara is startled and not sure what to make of it, so she waits. The knocking continues. This time louder and more frantic. It's coming from the front door and it turns out that Mara is not alone after all.