Hanasaku tabiji (Flowered Journey) - S2.E3

The Nirvana arrives at yet another planet tampered with by the Harvest fleet, as its inhabitants are unable to survive the air and have all caught a disease that is fatal, with no cure. On a mission of mercy, Duero and the rest of the crew stop at the planet in order to ease people's suffering and help them, and Bart befriends a little girl named Shirley, also bedridden with the disease. However, yet another enemy attack threatens the crew's only attempt to create a clean environment for the inhabitant's babies to be born in, and a reluctant yet determined Bart must leave Shirley to fight for her life while he fights to defend the planet from attack.