Set mainly in rural Japan and shot in sepia, Eureka tells the story of a young boy and girl who are on a bus when it is hijacked by a crazed killer. They, along with the bus driver, are the only survivors and flee together. But upon their attempted return to their normal lives, Makoto becomes a suspect in a series of murders and the children become orphaned. These numerous unfortunate events bring the three, along with the orphans’ cousin back together, forming a family and working toward reconciliation from the shared hijacking experience.