It's surely happened to every writer at least once:
A scene has popped into your head. You can see it clearly from start to finish, recite every line spoken. There's just one problem: you can't bring yourself to write the surrounding story.
Maybe you can't for the life of you figure out how they got into this situation. Or maybe you just can't figure out an ending that you and the readers would all be happy with. Maybe it's a longer tale than you're willing to tell, or you just don't want to do that much research into 16th century Florence.
So, don't.
Just write the scene, zero context given. (Maybe an author's note if you feel generous, but don't even feel pressured to bother with that.) We don't need to know why Lois and Superman are trapped in a cheese factory; it's okay if we never learn whether CJ Kent returns to his own time; we don't need an explanation for how Lois and Clark came to be herding dinosaurs in Colorado. Just go for it, and cite this challenge as your excuse for why we'll never find out how Lex came to own the entire state of Kansas.
And if you don't already have an isolated scene that's been begging to be written, feel free to make one up.
