Picture a AU (n15s1) where Clark did not return from his first attempt at stopping Nightfall.
Into this universe Tempus dumps a non powered Clark Kent from another AU (n16s3) during the time when Lois Lane was Ultrawoman.
But in n16s3 the Ultrawoman events occurred AFTER Lois and Clark were already married.
And he dumps UltraWoman as well. It is UltraWoman who has to stop the rest of Nightfall.
So now we have an AU with a missing Superman, a UltraWoman and a non powered Clark.
Clark of n16s3 is of course more distant in manner toward the N15s1 Lois, who is grieving
Superman's death.
Clark also can't completely hide his feeling for his Lois (n15s3 UltraWoman) from the sharp eye of Lois Lane (n15s1).
The Clark and Lois of n16s3 are both living at the apartment of the missing Clark of n15s1's.
Lois uses a wig and avoids meeting her Alternate self. Everyone at the Planet thinks Clark went off the deep end during Nightfall and got married.
Both the n15s3 Lois & Clark know about lex Luthor and are working on bringing him down.
But the n15s1 Lois is still dating him.
Clark Kent married to UltraWoman, working at the Daily Planet, sometimes with a woman who is a lot like but clearly is not, his wife.
