A small accident occurred in the laboratory last month, which lead to an apocalypse. Not just an apocalypse, but a 'mos apocalypse'. What's a mos? A mos is a bigger version of a mosquito which was accidentally made by humans. They are not ten cm tall, not even 30 cm, but over one meter tall! It seems that these creatures want to reproduce, therefore they are looking for blood. That is the reason why there are many reports of people going missing. At first, we thought mos would become extinct in the first week. But we were wrong. Now they are everywhere and the number of missing people keeps rising. An emergency signal has been broadcasted. The AAS team received the signal and are here to take action. They said that they have found a way to stop this apocalypse and that there is no need to send more troops. It seems that every member of AAS has a mission. They said that once all missions have been completed, the apocalypse will end once and for all. This game consists of two game modes: single player and co-op. On single player mode: grab a weapon, exterminate all mos, and complete the mission! On co-op mode: pick your weapons and perks, think of a strategy, and survive endless waves of mos.