The plot, in this the last in the trilogy of Indiana Jones films, centres on the search for the Holy Grail, the most sought after Christian relic. Dr. Henry Jones, Indiana's father, has devoted his life to seeking out the relic, and his diary is central to the plot. The diary contains intricate drawings, notes, data, maps and descriptions of obstacles that will bar the seekers way, the culmination of years of research, which are clues to the whereabouts of the Holy Grail, which is hidden in a lost temple. Indiana is drawn into the search when his father mysteriously disappears and all he has to go on is his father's 'Grail' diary.