The Sneferu family's son has gone missing when he went to build a sand castle in the clay pit, we must help them find and bring him back.
He fell into a cave complex through a hole, but we can't jump in the same way, we must go through a nearby shaft:
We see the son, but can't reach him directly.
Dig the wall, then use the lever to open bridge, and another lever to open gate, and we finally reach the son.
He doesn't readily agree to come with us and needs a doll first, so we have to go further fetch the doll for him.
Once you get the doll, return to the town and talk to the family to complete the quest.