In a story that moves through different time periods, mostly between 1968 and the present day, two teenagers (cousins) in the present day are learning the truth about the deaths of their parents, which appear to be tied to a murderer who has been a fugitive for over 40 years…

From MangaHelpers:

One day, 10-year-old Yamato and his friend Miku discover a man dying in a back alley from stab wounds. The man recognizes Yamato, and uses his last words to share a terrifying secret with the children: Yamato's father was a criminal involved in a bank robbery in 1968, the unsolved crime of the century. He also urges them not to trust anyone. After he dies, Miku and Yamato agree to keep his last words a secret. Only days later, Yamato's father is found dead, and he is taken in by Miku's parents. The death is ruled a suicide, but Yamato has his doubts.

Six years later, Yamato still can't stop wondering about what happened so many years before. Will he ever be able to uncover the truth about the crime in 1968 and his father's death? [tethysdust]