Vienna, 2056. Raleigh Hillbury, an engineer, notices irregularities in computer systems that make no sense. People brush it off as bugs and call in extra code reviews but no matter how hard and long they fix potential causes, the irregularities persist. Even a large-scale academic code review finds that these errors should not occur. Still, nobody has even the slightest idea of what is lurking beneath the neon-lit high-tech Garden Eden that is Raleigh's hometown.

Armed with their wits and scared out of the same Raleigh tries to get to the roots of these problems only to find out that by now they have stretched to almost every electronic device on this planet, even the analog ones. As they try to convine others to join them in their efforts to stop this unimaginable horror, started by a now retiree who was just fooling around with stuff on the computer her parents got her for her birhtday as a teenager, executing an image as a lua program they run into hurdles, as neuroatypical people's claims are quickly brushed off as delusions.

Through sheer coincidence Ashley, who accidentally created "cth.lua", as Raleigh has come to call it, finds out about their efforts and offers to joins them, even though she is struggling with her health. The two try to work out a plan to stall the program's progress in its unrelenting efforts to bring as much suffering as possible to humanity until someone finds a way to deal with it.

But are two code monkeys really all it takes to save the world?