When a girl wakes up in an unknown place, not remembering her past or her name, what will she do?

Serena is, as the title may suggest, a siren. Everyone she knows, loves, and trusts (well, mostly) has taught her that all sirens were meant to do is kill, and look pretty. -pshh like that's gonna happen- And to Serena, that just felt... wrong. She never really believed that it was good to sing your heart out to someone, just so you could pull him down to the depths of the murky waters of the cruel ocean and drown him. I mean, don't you think that's kinda... Harsh? So when it comes time to prove to everyone that she is a good siren, AKA, commit homicide to an innocent sailor, what will she do?