Chronologically episode 10.  Haruhi is determined to investigate the death of Keiichi and Kyon is dragged along with her.  When they head out to check on the boat, Haruhi sees someone in the cliffs.  When they investigate, they are trapped in a cave.  Here Haruhi tells Kyon her theory about how Keiihi died and not everything adds up.  Later, Kyon and Haruhi discover more to the plot of the dead villa owner and inform the others about their findings.