Mystery in Space #65 (1961)

While waiting for the Zeta-Beam to hit in a tropical jungle in Madagascar, Adam Strange finds himself attacked by a giant man-eating plant. Using his ray gun to blast free, Adam manages to catch the Zeta-Beam and be transported to Rann. There he is greeted by Alanna. She tells Adam that there is now nothing to menace the people of Rann ever again. She explains by telling the story of great scientist named Evar Ronokol from the planet Taragal. Seeing that the two super-powers of his world threaten to destroy it with atomic weapons he built an army of indestructible "Mechanimen" to pilot large machines in order to maintain peace and prevent war. However, Evar was too late and his planet was destroyed by atomic bombs and everyone was exterminated. Finding no survivors, the Mechanimen left Taragal for the stars to find new planets to continue their mandate of maintaining peace. They soon arrived on Rann to maintain the peace, destroying any weapons they found. Taking Adam to the newly rebuilt Ranagar City (after the events of last issue) she shows him that the Mechanimen are busy protecting the city. Going for a picnic, the two lovers are interrupted when they are confronted by a Tigrabar. When it prepares to attack it's quickly destroyed by one of the Mechanimen. Later that day, the Mechnimen warn the people of Ranagar that there is an impending invasion that they will fight off. Considering the possibility that the Mechnimen might not be able to stop the invaders, Adam asks Alanna if they still had their underground cache of weapons (Which was last seen in Mystery in Space #54) When Alanna explains that they forgot to mention the cache of weapons there to the Mechanimen, Adam tells her not to tell them and the two go in the dark of night to get weapons for themselves. Having found out what Adam Strange and the others were planning, the Mechanimen intervene and destroy all the weapons in the cache. The next morning they begin to defend Rann from invasion, however the Mechanimen -- in the mission to make Rann peaceful -- neglected to recharge themselves and soon run out of power mid-invasion. Adam and Alanna quickly take control of one of the Mechanimen's saucers and by salvaging weapons from the aliens own recked cruisers manage to force them to surrender. With the alien invaders defeated, the people of Rann also have new weapons which they can take from the invaders ship. With everything resolved on Rann, the Zeta-Beam wears off and Adam is once more returned home to Earth.