Ziva is introduced to the show as an Israeli citizen, an agent of the Kidon unit of the Mossad, a daughter of Mossad Director Eli David, and a friend of NCIS Director Jenny Shepard. She was assigned to NCIS as a liaison officer in an arrangement between Eli and Jenny, a position she held for four years until she returned to Mossad in the season 6 finale, "Aliyah". After being captured by terrorists in Somalia while on assignment for Mossad and presumed dead, she was eventually saved by Gibbs, Tony, and McGee, who brought her back to America. These events led to her resigning from Mossad, applying to become an NCIS agent, and being sworn in as a U.S. citizen.