When a master assassin\'s family is captured by an evil king he must commit a series of murders whilst trying to free his family and escape

Using the different names "soverign/tyrant" kinda makes it refer to someone else, didn't want to use "king" to much...ignore the post, sorry.

When a retired assassin?s family is captured by a sadistic king, he must remove those who threaten the sovereigns throne or else his family will feel the tyrants wrath.

Sounds better - "retired" indicates that he has left the life, and is being forced against his will back into it, so we have a good indication of conflict that's likely to arise.

Is there some way, without divulging too much, that you can make it clear who the targets of the murders will be? A series of murders, for instance, is less enticing, than say, the murder of every member of a rival royal bloodline, or the murder of the king's illegitimate children.

Also - instead of "whilst trying to free his family and escape," does it work if you change it to "in order to free his family and escape"? It strengthens the connection between the two concepts, and makes it clear that the choice is "do this thing that the protag now finds ethically problematic," or else "the protag's family will remain in danger."