How does ‘overambitious’ as a character flaw relate to the cause and outcome of the plot? Isn’t a character flaw supposed to be a causal factor, a prime reason the character unwittingly enables the dramatic caca to hit the fan? Or why a character is initially unable to cope with the caca that hits the fan?

And doesn’t he have to overcome that flaw as a dramatic pre-condition to (finally) solving the dramatic problem — in this case find the lone survivor? How does being overambitious prevent him from finding the sole survivor?

And it should not be the case that the sole survivor “may be the key”? He is the key. Period.

Also for your consideration, I suggest a variation that intensifies the motivation for the quest. What if it’s her beloved (older) brother? The back story is he was forced into indentured servitude by the father who needed the money, couldn’t afford to feed an extra mouth. Now there are reports the ship he was on was attacked by pirates.

Now her father bitterly regrets what he did but is to infirm/timid (whatever) to try to rescue him. So she does, to save her brother and right the wrong done to him.

And an additional risk to her is that if she’s unmasked by antagonists, she will be sold into slavery, too. Young women, particularly virgins, were even more profitable prime ‘meat’ for the slave trade. And that is a plot reversal could set up an entire season of harrowing adventure: what she must do when she is outed and sold into slavery herself?

[It seems to me to be too easy for her to be outed by friendly folks who then become allies in the quest. Rather, the stakes and risks — hence suspense — must continually escalate. She should succeed the old fashioned way — earn it every step, every episode by her own wits and courage.]

fwiw