Lois & Clark: The New Adventures of Superman (1993)

S02E18 Tempus Fugitive

Lois and Clark embark on a journey to 1966, aided by H.G. Wells and his time machine, to thwart a future villain intent on eliminating baby Superman. As they navigate the past, the antagonist reveals to Lois a crucial piece of information—Clark's most guarded secret: his true identity!