The Diary of Fireflies

After both of his parents died of cancer, Kai, a med student, quits his study and always hides at library to sleep. He then meets Rin, a dynamic girl, who has a big love for photography. He is then dragged everywhere with her to stop being deep in sorrow. At the same time, Rin has a rare disease that stops her being with Kai all the time, and also makes her separated parents being back together.