Everything sounded the same but Curtis couldn't help pick up on something being off with Frank. Like the man was trying to tell him something wasn't on the up and up. It wasn't as if Curtis didn't know you couldn't kill a disease with a gun. The fight was against those purposely spreading it. You could kill them with a gun... right?

"Experiment?" His face held as much confusion as the one word question. "What are you talking about, Frank? This entire thing is some sex trafficking ring?" Had it been Billy or, really anyone but Castle, Curtis would've thought they were messing with him. It would have to be a joke. Frank wasn't really the pranking type. At least, not about sex. He wasn't the Marine who would tell raunchy stories about his private life so telling him he'd have to have sex... Curtis just stared incredulously at him.