Si Vis Pacem, Para Bellum

Kensi and Deeks disappeared while on assignment; and the Office of Special Projects is picking up the piece. While working a case Callen and Sam see two people wearing cloaks and masks wrecking havoc in Los Angeles, but only with each other. Who are these maksed figures, and will Kensi and Deeks ever return? The entire O.S.P. is involved.