U.N.C.L.E. agents Napoleon Solo (Robert Vaughn) and Illya Kuryakin (David McCallum) are being attacked with missiles from small helicopters while on their way to see Dr. Simon True. The attackers work for THRUSH and, though they fail to stop the agents, are the titular “Karate Killers.” Dr. True has discovered a process to extract gold from sea water. Fearing theft, he hid the formula, saying someone would have to “hunt down the four winds” to find it. But during his presentation of the process to U.N.C.L.E., he dies from apparently natural causes (though we later discover is due to Randolph’s doing). True's dying words are that his daughter is the key to finding the formula. As the head of U.N.C.L.E., Alexander Waverly (Leo G. Carroll) informs Solo and Kuryakin that the dead man has four step-daughters and one biological daughter, Sandy True (Kim Darby). The consensus is that Dr. True sent each of his four step-daughters something that, when assembled, will mean something to Sandy and from which the formula can be discovered. (thetvdb.com)