I also started a story on a similar premise to Ministry of Time, but couldn't figure out where to go with it. (In my case it was "what if you could grab doomed people whose death was a little mysterious and bring them to the future, and a wealthy older woman started collecting people from the past, and one of the people she collected was the Italian painter Caravaggio?" (Brilliant artist, profoundly terrible person.) Never really progressed beyond the idea stage.)