Survive in an infected world.

During excavations in Antarctica, unknown bacteria 500,000 years old were found under the ice at a depth of 5 km. As soon as the bacteria were unfrozen, it turned out that they were not only alive but also extremely aggressive, because the first infected underwent metamorphosis after only 2 hours. It was only because of their survivability and contagiousness that the "zero patients" were able to get out of the research complex and continue the infection. As a result, 25 years later, more than 75% of the earth's land and 25% of the earth's waters were irretrievably infected and transformed into their ecosystem.