"œDescent" Pictured (L-R): Natasha Alam (Veronica Pisconov), Timothy V. Murphy (Isaak Sidorov) and Aunjanue Ellis (Michelle Hanna). An explosion in the desert rekindles the search for stolen nuclear weapons and prompts Hetty to shuffle the NCIS: LA partnerships, sending Callen and Kensi overseas and Sam and Deeks teamed up stateside, on the fourth season finale of NCIS: LOS ANGELES, Tuesday, May 14 (9:00-10:00 PM, ET/PT) on the CBS Television Network. Guest stars include Aunjanue Ellis as Michelle Hanna, Christopher Lambert as Marcel Janvier and Timothy V. Murphy as Isaak Sidorov. Photo: Sonja Flemming/CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved.