Hermione grinned and blushed, but they moved on. Throughout the day, everywhere they went they saw signs of tighter security; Professor Flitwick could be seen teaching the front doors to recognize a large picture of Sirius Black; Filch was suddenly bustling up and down the corridors, boarding up everything from tiny cracks in the walls to mouse holes. Professor Snape had taught every Slytherin stunning spells in case he came to Slytherin.