"Swallowtail Butterfly" is a Japanese film directed by Shunji Iwai. The story follows a young girl named Ageha who is abandoned by her mother and forced to live on the streets of Tokyo. She eventually finds a group of outcasts who take her in and teach her how to survive in the harsh urban environment. As Ageha grows older, she becomes involved in the world of underground crime and must navigate the dangerous and unpredictable world of the city. The film explores themes of survival, friendship, and the search for identity in a society that often marginalizes those who are different.