Fujimaru Takagi looks like an ordinary high schooler and works on the side as a top hacker under the handle Falcon. When Japan's intelligence agency Third-i recruits him to crack an encrypted chip, he uncovers footage of a virus that killed thousands in a Russian village, tied to a plot code-named Bloody Monday. With his father, a Third-i officer, framed for murder and a terrorist cell already operating in Tokyo, Fujimaru is pulled into a race to keep the same outbreak out of Japan.