In Dying Light, you're dropped into the jump boots of Kyle Crane, a contractor sent to the fictional city of Harran. It's been a few months since a strange disease broke out in Harran, and you're on a mission to recover some stolen information. To that end, you parachute in, immediately finding yourself surrounded by hostiles, both living and undead. Ingratiating yourself with the locals means that you need to gain their trust, and that means it's time to do some missions.
Dying Light is a game about avoidance, or at least that's how it's presented. There are zombies, but they can't climb very well. To avoid them, you're going to learn to be an expert at parkour, but don't expect Titanfall / Mirror's Edge wallrunning here. Climbing, jumping, and running are your entire arsenal.