Wow. Brilliant. Time travel creates never ending circles. Love it!.
BUT Flark and Flois will not be killed - well, they will eventually be if they leave things as they are..
"It's true, we could leave things just as they are now, but eventually - and most likely quite soon - a ripple will be created that could destroy everything."
It is only the current version of the future that will obviously change when the Lois's are changed back
It was only this version of the future that ceased to exist - not him or Lois.
In fact the new altered future might be really good - I mean, Plark and Plois would have married a lot sooner, without a lot of the angst, and will have had children already - so the new future will have none of the horrid memories, including the one that they cannot have children.
Oh, BRING ON NUMBER 10 - I'm getting quite excited here.
