Lin knows what "duty" means before she knows the definitions of much more elusive terms, such as "sacrifice" and "obligation." She knows that duty is late nights and early mornings spent sitting by the door, waiting to be sure that her mother made it home just one more time. Duty is the darkness that pools itself beneath her mother's sightless eyes, the bags that have no right to make her look as though she hasn't slept since before the war. Duty is never knowing if the police caught the bad guy, but praying that even if they didn't, she would not lose her only parent to the cause of catching him. Duty was joining the police academy at sixteen, graduating at eighteen, and becoming the Chief of Police at twenty-two. Duty was giving up your own safety to preserve the lives of your neighbors, friends, and family.
Duty was a scary, scary word, and Lin never grew to like it, because once out of childhood, duty kept her away from the one thing more important to her than her responsibility to Republic City: Tenzin.
Tenzin had always hated "obligations," as his father called them. They involved getting up at the crack of dawn to meditate, feeding the flying bison thrice daily, making his bed, cleaning his room, helping to set the table. Obligations ate into his free time, into his leisure, and he hardly had any time for playing as it was. Obligations made his back ache with the strain of keeping it completely straight as he meditated. They made his fingertips shrivel up from washing the dishes in the sink. They made him hold his breath as he cleaned the excrement out of the bison's caves. They made him miss his father on the nights when council meetings ran late.
Obligations were terrible, terrible things, and he did not warm up to them, especially when they started to tear away at his relationship with his childhood friend, Lin.
One had a duty to the city, to what her mother had left behind.
The other had a duty to his heritage, to what would never come again if he did not produce it himself.
Duty defined the lines in the sand that neither could cross. And cross them they did, for better or worse.
Duty, after all, was just a scary word. And scary words can't hurt you if, for just a moment, you forget what they mean.