The Accidental Philosopher (Side Quest)
This is available in the south of Alexandria.
Speak to the distraught woman to be sent on a search for her son.
The beach she mentions is very close, just a little past the end of the docks.
There are several clues here you can investigate- blood in the water, blood on the sand, torn clothes, etc.- or you can just go the small house at the south outcropping here, which autocompletes the investigation.
Bust open the door and find Tefibi inside.
Escort him back home, though you'll mostly be following him. Stay close, because just as the beach 'corners' into the mainland, you'll be ambushed.
Kill the soldiers. There only three- two swordsman and an archer.
The screen may warn you that An Ally's Health is Low, but Tefibi will just be knocked down, not killed, on taking lethal damage.
Speak with Tefibi afterwards to complete the quest.
This now makes available the quest 'Higher Education'