When ideas refuse to go away!

I couldn't sleep last night.

The idea for my next Modern Extra kept morphing and developing and going round and round in my head. I guess this is a good thing, as the plot for this one is coming to me bit by bit but honestly, at 1am in the morning when I'd been up the previous night with a sick child and was exhausted, it would be nice if the ideas waited till morning!

That said, I can't nail down a conflict for this one.
The characters are so crystal clear it's fabulous but I can't think of one thing to keep them apart!
Hmm...must think...must think...and if that doesn't work, rest assured I'll be turning it over to you guys for inspiration. There'll be a book or two in it for you, promise!