This issue reprints FANTASTIC FOUR #91 (1969), although thanks to the editing out of two pages it's effectively a Fantastic One story, with only Ben appearing.
The story opens with an unexpected scene of several gangster types of the prohibition era discussing their upcoming purchase of Ben from the Skrulls, when they're interrupted by another gangster who owns the slave they want Ben to fight against. We then see Ben still restrained by his captor in a ship bound for that planet. Arriving there, he's greeted by a boisterous kid gang, naturally enough.
Following that brief interruption and a demonstation of the nerve collar holding him captive, Ben is taken in a truck and told about how escaped con Machine-Gun Martin was taken to this world from Earth years ago, and inspired its current look. Along the way they're attacked by a man in a bi-plane, of all things. Finally at the training center, Ben has a brief battle with one alien creature and is then put in a cell with his planned foe, Torgo.
A lot of fun this time, especially how Kirby mixes in the excellently drawn 1930s era scenes and people with the sci-fi elements. He pretty obviously had a lot of fun with that (fortunately he did have quite a few chances to draw that stuff in context with the crime comics before and after this era), and the several action scenes.
Joe Sinnott inked the now 18-page story, as well as the original cover (slightly modified for this reprinting to allow for the different cover layout).