You may encounter this quest during the Family Reunion or False Oracle missions, or just by passing by the Temple of Amun. You'll hear the piteous wails of priests begging for help- open their cages to free them, for a total of five captive priests. If you have this quest selected, Senu can find their locations automatically.
There two caged behind the merchant/trader in the center of the complex.
One toward the northwest, above the western entrance.
One toward the southwest, under the garden trellises.
And the final one on the lower level of Medunamun's house.
Freeing the last one instantly completes the mission