Mary responds to Allesandra, "Gertrude was fourteen years old. She was far too innocent and trusting to face the harsh reality of Barovia."
The party does not find any out of the ordinary tracks.
Gertrude's room looks reasonably normal for a young child, decorated with painted images of unicorns, handsome princes, and faery castles.
As is normal for most of the houses in Barovia, the windows are covered with heavy shutters. Except, Cedric notices, for the window in Gertrude's room on the second floor.
One of the shutters is missing from Gertrude's window. But the only way to reach that window from the ground would have required a ladder.