Heartlander
What if the roles were reversed?
Natasha Romanova is a young SHIELD Agent who has just received her next mission. Over the last several months, SHIELD has been having her work with recruits and training with various other agents trying to find her a partner, and it is a relief to be back in the field again, even if it's only for one assignment.
Her orders are to track down world class assassin Clint Barton, who is currently in Budapest, Hungary, on an assignment to track down a fellow assassin from the program he was trained in that has gotten cold feet and is on the run. Having managed to shake every other tail put on him, Natasha is SHIELD's last hope at stopping Barton before he carries out his latest orders and takes off to the wind again, but both assassins' missions go entirely off plan with one single word.
"No."