Try any of the following, in graphic novel format:

Alan Moore's Swamp Thing. Very little continuity knowledge required.

Bill Willingham's Fables. Well-written, and the only continuity she needs to know, she already got in kindergarden

Y: The Last Man

Ex Machina

Hey look, there's no Marvel on that list. That's because the only reason to enjoy Marvel these days is BECAUSE of the continuity!