Humanity is at the edge of desperation because of

some unknown virus, which broke loose from laboratory following an
experiment and spreads on the planet with a disastrous speed.
Developing in human’s stomach, insidious bacteria are destroying
immunity and becoming mortally dangerous. But you can annihilate them
and stop an epidemic on your own or join efforts with other gamers all
over the world. In order to survive and stop an epidemic you must
obliterate bacteria with murderous antibiotic for them.