Stuxnet is the case study that opens this film: a piece of self-replicating malware built by the United States and Israel to physically destroy centrifuges in an Iranian nuclear facility, which then escaped its target and spread across the internet. From there the film widens into the market that made Stuxnet possible, the trade in zero-day exploits, security flaws unknown to the software makers themselves and therefore unpatched and unprotected. White-hat hackers who work to find and close these holes sit across from black-hat hackers and brokers who sell them instead, sometimes to governments building cyberweapons, sometimes to whoever pays most. Interviews with hackers on both sides of that line lay out how a backdoor gets discovered, priced, and sold, and why an unsecured internet is profitable for the people selling security back into it. Produced by VPRO's Backlight strand, the film treats the zero-day trade as a shadow arms market with no regulation and no rules, running underneath the ordinary internet everyone else uses.