"1 Litre of Tears" is a Japanese drama based on a true story that follows the life of a 15-year-old girl named Aya who is diagnosed with a rare degenerative disease. As she struggles to cope with her illness, Aya decides to keep a diary to document her experiences and emotions. Through her diary entries, viewers witness Aya's determination and courage as she faces the challenges of her illness. The drama explores themes of love, family, and the importance of never giving up in the face of adversity.