Olga, the ‘fianceé’ of the robot Link, hasn’t been seen for several days. Link, Nathan and May ask Hashimoto for permission to do some research in the Valley of the Dinosaurs. But while the agents are on their way there Hashimoto is ordered by Yabuno to forbid anyone entrance to the valley. And this is not all, for he must then take a plane and go with Tochiro and Reiko into orbit and destroy the valley. But meanwhile Nathan, Link and May have entered into the valley where they have found Olga, Ran, Minako and Fushiwara…
Page 95-96., mysterious invaders were actually Atlantidians (the first appearance of the Atlantidians in NN universe!) which will play an important role in the Atlantidian mini series which consists of episodes NN 59-65. Atlantidians story is often seen in Martin Mystere adventures and this is a spin-off.