You don't even have to know Death Note, think of it like that "Superman in the real world" story or miniseries(I forgot its name).
Just add teen angst and government funded teen genius investigator Lex Luthor.
It would basicly be the first season of Smallville -relationship stuff, but with mindgames and a silver-age-ish teen Lex Luthor trying to use convoluted plots to find out the identity of the superman before Superman finds out his (becasue anybody on the planet is an easy kill).