Luna drifted out of Slughorn's party, humming a tune and not paying attention to her surroundings. So much so, that she entered the first toilet she came across without glancing at the door. "I can't do this any more. I'm alone! No one can help me!" said a somewhat hysterical male voice from inside one of the stalls.
Luna stopped in her tracks and ceased her humming. That almost sounded like Draco Malfoy...
"You're not alone. I'm here."
"Fat lot of good you are. You're dead. You can't help me." he retorted, before flinging open the stall door. He looked ready to storm out of the toilet, except that Luna was standing in the way.
Myrtle floated out of the stall behind him, and looked quite surprised to see her there. "What are you doing here, this is a boys' loo!"
"I could ask you the same question."
"Get out of my way, Lovegood."
"Wait! You should put a memory charm on her. What if she tells what she heard you say?"
"I didn't say anything incriminating, besides which, how could she explain why she was in a boys' toilet?"
Myrtle's lip quivered, and she went wailing into a nearby sink. Draco watched her leave with an expressionless face.
"I think... that you're not alone. There are people willing to help you if you simply ask."
He scoffed. "Are you willing to help me in my task, even though you don't know what it is?"
She pondered for a moment before answering. "Yes, I would. Despite what a horrible person you are sometimes, I know you have some redeeming characteristics."