Someone has come to Metropolis. Maybe it's
another hero, or maybe it's a
sinister villain. Lois and Clark try to deal with this new good/bad guy...
BUT...
Things aren't always what they seem, and what Lois and Clark
thought was a new friend/foe was actually
the complete opposite.
Maybe this person is an impostor trying to ruin the original's reputation, or maybe they're a version from an alternate universe where they chose the other side of the force. Either way, the background check is not quite going to match up with what Lois and Clark find themselves dealing with.
The only rule is that this visitor--whether hero or villain--must be somebody who exists in another series; nobody made up from whole-cloth for the fic, and nobody who regularly exchanges punches with Superman in a slightly different canon. Other than that, fics can be any length, type, or time-period, so feel free to go nuts!