Your protagonist just found out that you boyfriend/girlfriend is a part of the gang. Not only that, he/she is the Gangleader. Expressing how your protagonist felt, write a lovely short story how he/she dealt with it and what happened next. Let loose your imagination.
The Rules are:
1. You have to include some kind of action anywhere in your creation.
2. Please kill someone in the story. It should not be your protagonist. (I like sudden death but don't make me cry.)
3. Every Gang has a rivalry. Make one of your choice.
4. Add some emotions. That will make your story better.