after failing three huge missions an assassin is given a opportunity to get to the top by killing the most dangerous and powerful drug lord/Mafia in the country… but his past come to aunt him when he finds out its his oldest daughter

When the new young hot head is enthroned head of a mafia family, an aging hit man is ordered to prove his loyalty and competence by killing a witness: his own estranged daughter.

The emotional complications would amp up the script, but that is too much detail to cram into a logline. (And if the boss gives him the job to prove his loyalty, then it follows that the boss questions his loyalty as much or more than his competence.)

what if the daughter is not only a drug lord but also a loving mother and wife that the dad didn't know about because they stopped talking but as he now sees her in a new light he then starts developing emotions for her but also need his job and need to prove that hes loyal to the boss and what if the boss knew that it was his daughter and purposely gave him that job JUST so that he would see how loyal he was