This 7-page Kirby Ayers story is reprinted from STRANGE TALES #99 (1962). Apparently after several failed attempts at making robots, an inventor named Morgan finally came up with a decent design in 2090. The robots worked fine (oddly the tasks we're shown them doing are vacuuming and directing traffic) but were feared by people and outlawed. Morgan sends them off a cliff, but secretly keeps one alive, hidden under his house, for the day when humanity can accept the robots.
Then one day aliens secretly land in a cool looking ship...
These aliens apparently don't do well with confrontation, as they gas the city and sneak in, hoping to steal the robot, copy his design and use their robot army to invade Earth. Unfortunately for them, the creatur remains loyal to humanity and steadfast in his insistance on obeying Morgan's order to stay undergound, delaying the aliens enough that the gas starts to wear out. The cowardly aliens blow up their ship and themselves rather than be detected by the humans, leaving the robot damaged and dying on the street. Morgan assumes that the robot had disobeyed his orders to stay hidden and humanity was right to distrust the robots. The robot dies with a tear in his eye, with no one knowing of his sacrifice for humanity.
Definitely one of the highlights of the Kirby/Ayers monster stories, this is a very well drawn and touching story.
As usual for Marvel Monsterworks, you can check out the MonsterBlog for more on this story.