Secret Door. Iron, no lock. DC 13 to spot, no check if the Open Book is read. If found, a small glowing glyph appear which opens door if touched. The door is Trapped.

Trapped. Touching the glyph in the wrong spot creates a 5’ cloud of ethereal daggers centrerd on the door. Creatures make a Dexterity save DC 12 if they start their turn or move into the cloud for 2d10 force damage, or half as much on a successful save. Disarmed by touching the glyph in the right spot, requiring an Intelligence (Arcana) DC 15 check to discern. Shining a light on the glyph reveals the correct spot.

Secret Room (S1) 5’ square chamber contains Boots of Elvenkind and special scroll of Comprehend Languages usable by non-mages.

East Passage (Ab) 10’ wide stone passage that continues 20’ straight with an iron locked door to the right. Dexterity (Thieves’ Tools) DC 12 to unlock. The Rusted Key opens the door. Leads to B.

West (Ac): This wooden and unbarred 10’ tall door directly adjoins chamber A and leads to C.