A couple of tourists are fatally shot on a hike by a top secret military drone, taking priority over the 'couple therapy' the governor imposed on Steve and Danny as part of Five-O's annual audit. While Jerry helps work out the probable manufacturer, it strikes again, murdering people arbitrarily on a beach. People are told to hide inside while the team pursues leads to a manufacturer-fired rogue and Jerry tries to disable the drone with Steve and Danny as bait, but there's another player arriving. Meanwhile Adam and Chin hope to deal with old baggage.
—KGF Vissers