In World War II Japan, Setsuko and Seita are a brother and sister whose mother has recently been killed in and air raid, and their father is a soldier, fate unknown. They must struggle to keep themselves fed and sheltered, the only pleasure from life they currently draw is watching the fireflies.
Don't let the fact that this is from Studio Ghibli trick you into thinking you'll be watching a cute tale of big-eyed girls and fuzzy monsters. While it shares the engaging visual depth of, say, Ghibli hit Spirited Away, Grave Of The Fireflies is a very sobering, adult tale of how the bombing of Japan during World War II affects two impoverished children, determined to survive on their own terms.
A devastating heart-stab of a movie, this certainly isn't a family film. It is, however, a beautifully constructed, animated drama.