Speak with Erinna in Korinth. After a short conversation, follow her to Lechaion Port. She will ask that a fellow hetaera is rescued from pirates.

Destroy and board the pirate ship a bit out from the bay. Do not cleave the ship in half, as Kleio, the woman meant to be rescued, will die. Continue chipping away at its health bar until boarding.

After all enemies have been slain, a conversation with Kleio will begin. As it turns out, she was trying to get out of Korinth. Either take her back to Korinth, or escort her to her destination in a side quest, Escort Service, later on.

Return to Korinth and speak to Erinna. Tell her what happened with Kleio, and after the conversation ends, the mission will come to an end.