A locking system and method of manufacture can include: a cargo container having a first container door, a second container door, and a container frame base; a lock box affixed to the second container door, the lock box extended into and through the second container door, the lock box including a sliding lock rod configured to extend behind the first container door when the lock box is in a locked configuration; a sliding lock rod guard affixed to an exterior surface of the first container door and affixed to the exterior surface of the second container door; door guards affixed to the second container door and the first container door; and a drop lock affixed to an interior surface of the first container door, the drop lock including a drop lock rod configured to extend down into the container frame base when the drop lock is in a locked configuration.