As detect secret doors except as noted here.
You can detect secret doors, compartments, caches, and so forth. Only passages, doors, or openings that have been specifically constructed to escape detection are detected by this spell. The amount of information revealed depends on how long you study a particular area or subject.
Presence or absence of secret doors.
Number of secret doors and the location of each. If an aura is outside your line of sight, then you discern its direction but not its exact location.
Each Additional Round
The mechanism or trigger for one particular secret portal closely examined by you. Each round, you can turn to detect secret doors in a new area. The spell can penetrate barriers, but 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt blocks it.
If you pay 4 additional power points, this power's duration is changed to 1 hour. During the 1-hour duration, you must concentrate on the power to gain information from it (as noted in the detect secret doors spell description), but a lapse in concentration doesn't end the power.