Originally aired: December 28, 1969 on ABC
Writer: Jackson Gillis
Director: Sobey Martin
Show Stars: Don Marshall (Dan Erickson), Deanna Lund (Valerie Ames Scott), Heather Young (I) (Betty Hamilton), Gary Conway (Captain Steve Burton), Stefan Arngrim (Barry Lockridge), Don Matheson (Mark Wilson), Kurt Kasznar (Commander Alexander B. Fitzhugh)
Guest Stars: Alan Bergmann (Krenko) , Alan Hale Jr. (O'Reilly) , Dusty Cadis (Store Guard-Warner, Jr.) , Michael J. Quinn (Watchman Jake) , C. Lindsay Workman (Cunningham the Jeweler) , Billy Halop (Bartender Harry) , Eddie Marr (Peddler Brynie)
Production Code: 4716
A Giant, O'Reilly, is fleeing from security guards led by Krenko. He knocks himself out and Steve is forced to gag him so Krenko won't hear his moaning. When O'Reilly wakes up he sees the Earthlings and thinks they're leprechauns. The Earthlings take advantage of this to escape, but Fitzhugh decides to take further advantage of the situation. He goes back and convinces O'Reilly to start gathering repair parts, as well as beer and lollipops, for them. Steve is initially against the idea, but O'Reilly succeeds in getting some spare parts and the captain warms to the idea.
However, Krenko is still following O'Reilly, and wants to use him as the fall guy to cover up the fact he's been committing the robberies. He figures out O'Reilly is dealing with the illegal Earthlings, and plans to capture them as well.
The Earthlings need O'Reilly to break into a jewelry store and get important tools for their repair effort. O'Reilly takes them in, but is spotted by the jeweler. He knocks the jeweler out, then Krenko knocks O'Reilly out. The Earthlings manage to trip up Krenko and escape with O'Reilly, leaving the crook to be arrested by the police. In the end they tell O'Reilly the truth about where they're from, and he goes merrily on his way back to the country.