You create a ward that protects up to 2,500 square feet of floor space (20' tall). You specify individuals that are unaffected by the spell's effects and can set a password. The spell creates the effects below within the warded area. Dispel Magic has no effect on Guards and Wards itself, but each of the following effects can be dispelled.
Corridors. Fog fills all the warded corridors, making them Heavily Obscured.
Doors. All doors are magically locked, you can hide up to 10 doors.
Stairs. Web spell fill all stairs.
Other Spell Effect. Place one of the following: Dancing Lights in four corridors; Magic Mouth in two locations; Stinking Cloud in two locations; Gust of Wind in one corridor or room; Suggestion in one 5' square.
See PHB for full description.
Material Component:
a silver rod worth 10+ GP
Verbal Component:
Custos i Tutellos Protectio