Susie and Evan make the horrifying discovery of about 50 dead kangaroos, looking to have been ripped apart with an automatic rifle. As debates rage over whether or not to thin out kangaroo numbers, the farmer who owns the land where the dead roos were found comes under suspicion. He denies it and suggests a mate he served with in Vietnam might be responsible for it, thinking that slaughtering the kangaroos might send a message to not have a cull. As the Heelers dig deeper, it is discovered that a cache of weapons from Vietnam had been kept, but when they come to seize them, some turn up missing. Now the race is on to find the weapons and whoever might be holding them.