Ran is sick, moving with a weight on his shoulders, something draining his will and slowing every gesture. The others can tell that a strange misery is involved with the malady, although which causes which is uncertain.
Aya-chan's sickness is different. It comes in the morning, and goes as quickly as dew from the blossoms she tends outside the Koneko. Her color brightens, and is assumed to be a sign of recuperation from her long coma. It's weeks before she understands, and sinks to the floor in tears and confusion.
Ran accepts a deep-cover mission, and hopes never to return.