Luna drew a sketch of Dumbledore; it was very like him.
"Has anyone seen your drawings besides Ginny and me?" Neville asked.
Ginny interrupted him. "We have to take some risk."
"Yes, but if the wrong people know her drawings she'll get all the blame. It's serious. We're accusing Snape of killing Dumbledore."
"No one pays attention to me, except to hide my things." Luna looked serenely at them. She patted Neville's hand. "They never take my drawing book; it's with me all the time."
"Good, I'll hang the posters tonight." Neville said.
"We both will," Ginny answered.
"No, Snape will think of you when he sees this -- not me. -- He thinks I'm stupid and afraid of him." Neville felt his face go red. "If we make it look like you couldn't have done it. It'll confuse him."
Luna continued drawing. She didn't seem to care who hung the posters.
"I thought we're facing more than detentions. Real danger. Why should you take all the risk?" Ginny asked.
"I'm protected, Snape won't think of me as long as I'm careful." He gave her a huge grin. "Look what I learned last August." He rapped himself on the head with his wand and faded into the wall behind him. "It took me the whole month to learn, but I can do it. My great-uncle showed me; I think he believes I'm planning on sneaking into the girl's locker room."
Ginny snorted. Luna looked up to stare at him. He restored himself to normal visibility.
"Well, you're the one then and I'll spend tonight creating an alibi." Ginny grimaced. "I could stay up all night doing divinations with Lavender, Parvati and Padma. They always want the other girls to join them. -- I'd hate it though."
"Everyone has to sacrifice, Ginny," Luna said, as she sketched Snape.