From the introduction:
The adventure began when the boy Nefru, ward of the Temple of Anubis, was stolen from the town of Thinnes. After a long chase and a confrontation in the town of Ombos, the matter was satisfactorily resolved. However, a black metal collar of unknown, but evil, properties had been placed around Nefru's neck, requiring the party to retrieve a powerful relic from the tomb of an ancient sage, buried near the eastern city of Akhmen. You succeeded, and barely in time. Since then you have been resting in town, and some of you have completed your training.
Publisher's blurb:
The party rests and trains in a small town near the tomb. Here, they receive an immediate and mysterious summons home to Thinnes. They decide to save time by cutting across the desert out of season. Meanwhile, their activities have attracted the notice of the Unnameable One.