Tokyo Godfathers (2003)

Christmas in Tokyo, Japan. Three homeless friends: a young girl, a trans woman, and a middle-aged bum. While foraging through some trash, they find an abandoned newborn. Hana, the trans woman with frustrated dreams of being a mother, convinces the others to keep it overnight. The next day, using a key found with the baby, they start tracking down the parents, with many adventures along the way.