Grave of the Fireflies (1988)

During World War II, 14-year-old Seita and his 4-year-old sister, Setsuko, are left to survive alone after being separated from their mother during the bombing of Kobe. With their father in the navy and an indifferent aunt, they face hunger and hardship in a devastated city. Struggling for shelter and food, the siblings endure, contemplating the fleeting beauty of fireflies and life itself.