Gilad and Mark Peretz
Gilad Peretz, left, is searching for his father Mark, who vanished after Hamas fighters launched an attack on Israel on Saturday.
  • On Saturday, Hamas militants entered Israel and launched a devastating attack by land, sea, and air.
  • The opening salvo saw hundreds killed at the Tribe of Nova festival, not far from the Gaza border.
  • The son of a man who vanished trying to rescue his daughter from the festival is scrambling to locate him.

This first-person, as-told-to-story is based on an interview conducted by Insider correspondent Reed Alexander with Gilad Peretz, 26. Peretz's father, Mark, 51, went missing on Saturday, shortly after the Palestinian militant group Hamas attacked Israel.