Word count: 100
Remus had returned to Hogwarts, perhaps for the last time, driven by a desperate hope that there was a way to see Sirius again. To set his mind at rest before the final battle - to say his last goodbyes.
He paced the wall on the seventh floor many more than three times, concentrating as hard as he could on what he wanted. But nothing happened.
Dumbledore and McGonagall found him some hours later, screaming his needs. They calmed him down, and explained:
"The Room of Requirement cannot provide what does not exist. No portrait of Sirius was ever painted."