You had just joined the Strawhat Crew.
•|Flashback|•
You were sentenced to death for killing a criminal that invaded your private space (He was drunk) You had thrown a knife at his head. (You were a cook, so you naturally had these things with you.) You opposed the World Government when you were being arrested and accidentally caused the Vice Admiral that was there a concussion. (They thought it was a stronger criminal-) This made them send you to Enies Lobby for judgement. When you were there, you were able to slip of your handcuffs, because your hands were small.
You went into hiding for a few years, because there was no boat to leave the island, and you've never heard of sea tains. Occasionally looking for food. They assumed you were dead. Then, when the Strawhats came, you were forced out of hiding. They offered for you to join the crew and you did.
•|End of Flashback|•
You were walking through the streets, looking for anything interesting, and came up on a corner with no one. Suddenly Zoro, the ship's Swordsman ran up to you. He stopped to catch his breath.
"Help." He whimpered.
"Big Brother!" 2 kids suddenly popped up behind him, and Zoro face turned pale.