Storyline: At the beginning, you crashed somewhere in Panchevo industry zone (nearby Belgrade). You are only survivor from this crash. You are a Serbian soldier from 72th parachute brigade. You have no idea how to escape from this area. Looking around, you will see a bloody strangers. Later, you will see a special police SAJ units controlled by the goverment, with order ko kill every alive thing. So, you are forced to kill them until you get the command of SAJ units.
This is the first official trailer of TSOTS (SecretOfTheSickness):