Main Story - The Vet Clinic

When you reach the marker, you will meet a sheriff and a girl. Enter the vet clinic through the door behind and barricade the windows to slow down the zombies attacking while they are gathering meds. Go outside and kill the zombies. Again, dont dropkick zombies near the window as it will trigger window breaking, just smash your way through.

Once they have gathered meds, head outside and guide them back home. When there are hordes along the way, ride a vehicle and run them over, ignore them demanding you not to ride a car. Sometime after the sheriff will leave, then just ride a car back home, with the girl joining you inside the vehicle along the way.