Parasite Planet begins with Ham Hammond trekking across the surface of Venus. The environment is parasitic, filled with bizarre alien life forms like the lasso throwing Jack Ketch Trees and the doughpots, a mindless omnivorous ball of animate cells that devour all living things in their path. When Ham meets the contentious Patricia Burlingame, they have to march across Venus to safety. It's not clear what is going to kill them first, Venus's hostile environment or each other.
In The Lotus Eaters, Ham and Pat are on a special scientific expedition to the dark-side of Venus. They discover a strange warm-blooded plant. The most disconcerting thing about the plant is when it begins speaking English and waxing philosophically.
The Planet of Doubt brings the duo to Uranus on another special scientific expedition. The cloudy shrouded terrain strikes terror into the heart of Ham as tries to find the lost Pat who he hopes is still be alive!