This is technically a side quest, but it's about as main questy as a side-quest gets. To begin, track down your old friend Menehet in the Temple of Sekhmet at Yamu.
Speak with him again for a tour of the temple.
During a cutscene you'll meet all his kids, and they'll scatter in an impromptu game of hide and seek. Use Senu to track their locations (some will be moving, but the markers will move with them).
Do remember what weapons you have equipped, as the one outside at ground level (Soris), will accidentally loose a hyena.
The other three children are inside among the pillars (Nailah), trapped down a well (Keba), and on the rooftop stargazing (Hasina). For Keba, you'll have to bash down a door to escape through a short tunnel.
When all four sprogs are accounted for, return to Menehet. He'll be mixed up in some argument, but speak to him when he's available to complete the quest.