The impetus of history comes from betrayal. Yesterday's excellent student Yevdokia trustingly rushes to help her brother, but becomes embroiled in a showdown over the billion-dollar inheritance of the Zubov family and becomes a suspect in the murder. Trying to justify himself, Dusya unwinds a ball of ingenious combination and along the way saves the heir of those billions, major Ilya Zubov, from d...