Season 05, Episode 09 – What We Leave Behind
After Prometheus attacks Curtis, Oliver realizes Prometheus knows all of Team Arrow’s secret identities and is planning to come for them one by one. Meanwhile, Felicity and Det. Malone discover a clue that links Prometheus to Oliver’s past.
Oliver Queen and his father are lost at sea when their luxury yacht sinks. His father doesn’t survive. Oliver survives on an uncharted island for five years learning to fight, but also learning about his father’s corruption and unscrupulous business dealings. He returns to civilization a changed man, determined to put things right. He disguises himself with the hood of one of his mysterious island mentors, arms himself with a bow and sets about hunting down the men and women who have corrupted his city.