Day 41—Monday
The machine emerged from the placid sea and silently scampered up the sandy beach slope. It was half past three in the morning on the northern shore of the Bohai Sea. About the size of a fat laptop computer and shaped similar to the shell of a leatherback sea turtle, the crawlerbot propelled itself with two sets of articulated legs, five on each side of its six-inch high hull.
An autonomous underwater vehicle delivered the crawlerbot to its launch point, a hundred yards offshore of the target beach. Two weeks earlier, a Russian freighter from Vladivostok had released the AUV prior to calling at the Nampo seaport on North Korea’s western coast. The ship’s cargo holds were filled with spare parts for Russian military equipment purchased by Pyongyang.
After transiting the Yellow Sea, the AUV had parked itself on the bottom of the Bohai Sea fifteen miles from the target. At midnight of each day, the robotic submersible would ascend to the surface, extend its radio antenna and listen for orders. Tonight, those orders came—issued from the Kremlin.
The crawlerbot crested the beach berm and stopped inside a patch of dune grass; it was a hundred feet from the water’s edge. For the next minute, its electronic sensors probed the still night air for threats. Detecting none, its onboard GPS unit took a fix on the overhead constellation of Russian navigation satellites. Verifying it was within the specified limits of the objective’s coordinates, the robotic amphibian commenced the next phase of its self-diagnostic testing program.
The watertight seal over the cargo compartment opened, the lid on its outer shell rotating upward. A microdrone emerged from the opening. About the size of a golf ball, the drone hovered several feet over the crawlerbot. Its whirling propellers scarcely generated a whisper. For the next minute, the autonomous aerial machine with its payload of death verified that its onboard systems were functional.
After completing the tests, the drone returned to its cradle. The cargo lid closed and the amphibian buried itself in the sand, using its legs to dig. Left behind on the surface was an acoustic monitor released from the hull; it mimicked a clump of dune grass. A wire connected the microphone to the crawlerbot’s AI brain. During daylight hours, the computer would listen for a particular sound—the bark of a golden retriever.