In Rumfuddle, a genius scientist named Alan Robertson has discovered that there are an infinite number of parallel universes.
At first, this is heralded as a great benefit, as it has created a post-scarcity society; any raw resources can be harvested by going through a portal and getting them from a planet in another universe.
Bob gives access to the portal device to a small group of friends, who he calls "Rumfuddlers," to set up complex practical jokes that change historical figures.
The Rumfuddlers turn Nazi leader Hitler into a kosher restaurant worker and they make Marx, Lenin and Stalin into servants to Czar Nicholas.
Gilbert works on Earth but lives with his wife Elizabeth and three daughters in a parallel Earth-like planet called “Home” that he accesses via the portal.
Gilbert thinks the portal might be shut to him because he refused to meet his Grandfather’s elite friends, the practical joke-playing “rumfuddlers”.