In this episode the boys have to get back to their own time or else the girls will disappear (never to be born), though we don't see this problem in any other episodes.
Inconsistency: When the Book was shredded in this episode, the only thing that changed was that the girls were never born. However, in later episodes, all six of the kids note that if the Book is destroyed in any way, the entire universe will be destroyed with it.
Episode Order Goof: When using Samantha's pocket watch, she and the boys get caught in the middle of a battle with Custer's cavalry and a group of Native Americans. Fred says, "Hey, we missed you guys," when really the group had never seen them before because they were only in The Good, the Bad, and the Goofy which aired after this episode.
After Samantha returns to 2105 and it is explained why she has no legs and they all go off to get The Book, Samantha is supposed to have her legs dissappear, but she says she was wearing pants to cover.
This is the only episode so far that has the trio traveling into their future instead of into the past.
In the original book series, they don't meet the girls like this until the 4th or 5th book.
Samantha and Freddi do look like female versions of Sam and Fred, in a bizzare way, but Jodie hardly looks anything like Joe, and has a darker complexion.
This is the first appearance of Jodie, Freddi, & Samantha.
We learn that Jodie, Freddi, & Samantha are Joe, Sam, & Fred's great-granddaughthers.
Sam: (drawing Samantha) She's disappearing because we need to go home, get married, and have kids!
Samantha: My hair does not look like that!