What do you think of my idea for a fantasy novel series?

Ok so the idea just entered my mind a couple days ago for several books. Each one is about a seperate individual. The catch is they each live in a different world. It starts out when the last member of a royal family of 'Travelers' or 'Gate Keepers' is killed. Now that the Queen is dead it is up to the family of stewards to track down the one person who can take the throne. There is about five or six individuals that are tracked down that carry the bloodline of the original royal family, but that is the easy part. The hard part is convincing these people to travel using magic to another universe and see if the Queen's sword will accept them as the next ruler.