Celaena Sardothiaen is Ardalan's Assassin. She was raised by the wealthy Arobynn Hamel, "King of all Assassins," in the assassins guild, Arobynn's home. She is said to be the greatest assassin there is at age 17. Her rival is Sam Cortland.
Celaena and Sam were sent for a business transaction by Arobynn that turned out to be to confirm a slave trade agreement. Celaena and Sam decided to ruin the agreement and free 200 slaves. Both Sam and Celaena were punished for this drastically by Arobynn.
As punishment for freeing the slaves Celaena was sent to the desert to train with the master, an old and wise assassin. He ended up training her and she ended up saving his life. she spent a month there and was sent back with trunks of gold in order to pay off the debt she owed Arobynn and be free.
Sam was murdered in an operation gone wrong after Celaena realized she was in love with him, and they left Arobynn to be together. The target was the reason he died so Celaena wanted revenge, she ran right into a trap set by Arobynn.
Celaena spent a couple night in a cell until she was called in front of the king, who sentenced her to to 3 lifetimes worth of work in the mines of Endovier as a slave.
On the way to the mines Celaena had given up most hope on her life until she saw a white stag, the symbol of her home land, and it gave her the hope and will to survive.