"You are insane!" And he had to admit it was one of the few times in his life when he and Casey McDonald were in complete agreement. Unfortunately, insanity is not something you can choose anymore than you can choose to be the victim of someone else's father's lack of common sense.

Derek was currently sitting on the edge of Casey's bed while she paced the room. Her hair was wild, as were her eyes and he knew that any minute now she was going to unleash one of those tempestuous torrents of emotion that he knew and…ahem…liked her for. He just wasn't sure if it was going to manifest itself as tears or a right hook to rival Tyson.

Knowing his step-sister he'd go with Tyson.

His explanation of his idea to Bob Childs had been short. He had told Bob he would marry Casey.

And yes.

He was insane.

He told himself he was insane with love for his family and the knowledge of what it would do to them should they lose Casey and Lizzie. His family wasn't perfect but it was perfect for him. He loved how Edwin, the loner had found a partner in crime. He loved how Marti was growing up with two doting elder sisters and he adored his baby brother. He loved his step-mother with a tenderness that put her on a level with his own mother, and the happiness she and her little family had brought to his own dysfunctional one was worth any amount of pain to protect it and he was cut up about Lizzie being hurt.

The realisation that the only thing that had stopped it being Casey was the mistaken belief that he was dating the elder sister made him realise that he would perpetuate that myth till kingdom come if necessary.

If it would protect her.

But pretending that they were dating would not be enough. These mob characters while occasionally mistaken were not stupid. When they had spent enough time watching Casey and Derek they would realise she was not his girlfriend.

So it made perfect sense to Derek at least that he should give her his surname; make her his wife.

Temporarily.

Until this whole pig shit of a situation was figured out.

It didn't matter that he and Casey had a hate-hate relationship, although even Derek understood that was somewhat inaccurate. She rocked his world in all the wrong ways, but there was no escaping the fact that his life would be poorer without her in it. It was a big part of why he had agreed with George about sticking with Casey when they were hidden.

He needed Casey and she needed him.

Unfortunately, he now had to persuade Casey of that fact.

.

Bob's reaction to Derek's suggestion had been contemplative which surprised Derek because he had assumed it would get laughed out of hand. But Bob was not given to rash judgements so he actually thought about it.

"It sounds extreme." Was his initial verdict.

"I know. I hate the woman."

Bob did laugh at that. The family maybe on tenterhooks right now, but Derek and Casey were Derek and Casey and he had already been party to a couple of Derek and Casey "moments". They included one which ended with Casey needing a shower to wash maple syrup from her cleavage and another where Derek announced to his family he was going commando because Casey had "lost" all his boxer shorts.

It had taken Marti to diffuse the latter situation. The young girl had squealed "Ew! Too much information!" And then demanded that if Casey had lost Derek's underwear maybe she should lend Derek her panties, which conjured up a picture which had them all laughing so much that in the end Casey had returned at least one pair of his shorts and then stomped off in a huff.

"Let me get this straight." Mac said over the secure phone line to his office when Bob called him. "Derek wants to marry Casey to make her a Venturi and then, if and when this is over, dump her ass and return to a life of drunken debauchery and topless models."

"So he says." Bob said to his old friend.

Mac laughed. "Fuck me. The young never learn do they?"

Bob chuckled. "I'm tellin' ya. The sincerity…speaks volumes."

"Does George know?"
Bob shrugged although Mac couldn't see it. "Not for definite. But he has his suspicions and the one thing you should know about George… he ain't as clueless as he makes out."

"So what have you told Derek?"

"I told him he needed to be the one to tell Casey."

"Fuck…can you imaging that conversation?"

"Oh yeah! I'm thinking about taking a leave of absence."

"Chicken!"

"Hey! Why are you in New York anyway?"

"Fuck you."

Bob was still laughing when he hung up.

Derek approached Casey after dinner.

"We need to talk." He muttered and because it was so rare that he sought her out, she nodded.

"My room? Eight thirty?"

"Sure." He said and took his seat opposite his baby brother.

Throughout dinner, he watched his step-sister. And his observations troubled him. Here was the girl he had fought against for so long as a child…and now he needed to treat her as an adult. The problem wasn't that she made a bad prospect as a wife. It wasn't that she was ugly or bad company. It was to be blunt, the complete opposite. Casey McDonald was beautiful, intelligent, vital, and whilst Derek had fooled himself into thinking that he would settle for just a beautiful façade in his future partner(s), the reality was, Casey surpassed what he had anticipated for himself. She had depths he had never seen in anyone else; characteristics that called to him in frightening ways. There was a possibility that she was more than he could handle.

.

Eighty thirty saw the rest of the family sitting down to watch 'Finding Nemo', a prospect neither of the adult children could face. So whilst George and the younger four plonked themselves in front of the TV, Derek and Casey held a council of war in her room.

Casey led the way, her pants making a noise as her legs rubbed together as she walked into the room. Derek refrained from commenting on it and decided to speak only facts.

"I think you should sit down." He announced when they were finally in her room.

"Oh?" Casey said, her movements showing her nervousness.
"Bob knows why they picked Lizzie and not you." He said, cleanly, plainly, honestly.

Casey let out a breath. "Okay."

"You aren't going to like this. It's my fault." Derek admitted, although he thought she would be really unfair if she agreed with him. He continued. "You know the history your father has with the mob." He started. Casey nodded. "Well, it appears my family has a history with the mob too."

Her jaw dropped.

"What kind of history?"

"Three or four generations back, we were in Sicily. We were Family."

Casey stared at him.

"How long have you known this?"

"Since Bob was here. Apparently, my branch of the family distanced themselves from the mafia, but blood runs thick. Our previous connection with the cosa nostra gives us a certain, thin degree of protection. In some ways, the Venturi are untouchable. Steve was allowed to target McDonalds. He is not allowed to target Venturis."

"I'm a McDonald." Casey stated.

Derek scratched at his hair, nervously. "Yeah. What'd'ya know? Apparently they think you and I are dating, which makes you a temporary Venturi."
There was silence.

"How do you know this?"
Derek shrugged. "Bob says they were given the intell by an informant." He patted the bed beside him.

"Princess we need to talk."

There was something in his voice that made her sit down next to him.

"This immunity of yours is temporary. They find out that we aren't dating, they will attack you." He noted the frightened look in her eyes and took her hand.

"Casey. This goes against the grain, but I think the situation is serious enough for drastic measures."

"Oh?"
"They will work out that we aren't dating soon enough. I want to stop that happening."

"How?"

He took a deep breath and just came out with it. "I want to marry you."

.

Until this moment, he had never really had a problem with her laugh. He was rapidly changing his mind.

"Case…Case…Casey!" He shouted, breaking across the hysterics she was currently enjoying. He could tell she was enjoying it. She glowed.

"You are insane!" She announced.

He nodded. "Yeah. Tell me about it."

"Derek. Of all the low tricks you have ever pulled, this takes the prize."

"Casey. I'm serious. The FBI is talking about housing us together anyway; pretending that we are married. They are telling me you are in danger. They are telling me that danger would be dramatically reduced if your surname was Venturi. You are too old to be adopted so all I'm suggesting is that for a short, limited time we make your surname Venturi." He paused. "I'm asking you to marry me, sis."

She snorted.

"Like hell I will."

"…for Nora and Lizzie's sake."

"You bastard!"

Bob may well have left the announcement up to Derek. But when Derek asked him to he supported Derek's plan. The following day he came to talk to Casey, ostensibly about the relocation. The reality was he was there to lend support to Derek's harebrain idea.

"Casey. You're a bright girl, okay?" Bob started. "And I admit that what Derek is suggesting is a little unorthodox."
She stared at him in disbelief. "Your definition and my definition of "little" are rather different." She stated.

He leaned his head to one side.

"Casey. Right now, the whole family is in danger and if I had my way you would all be holed up in your own private wing of a maximum security prison."
"Are strait-jackets optional?" She asked. Derek smirked in the corner.

"You have requested that you be allowed to finish your college career." Bob went on. "The only way we can do that is if we find a situation whereby we can guarantee your safety. We had two choices for your scenario. The first had you and Derek behaving as siblings, possibly twins. But the disadvantage is that you don't look alike and emphasising this relationship sends a message to the mob clear as day that you are his sister and that is all.

Alternatively, we set you up as a married couple; high school sweethearts. That way, even if something happens to Derek, you are still a Venturi."

"Why not just pretend?"

Bob shrugged. "We could…but they are resourceful. They will check. A false paper trail will only hold them for so long."

"You're asking me to marry my brother." Casey snorted.

Derek crossed the room to her. "Look me in the eye and tell me seriously that you think of me as your brother." He demanded.

Casey looked him in the eye, but she found the warm softness in his face too much and she had to look away. Derek raised a hand to stroke her face.

"Me either, sweetheart."

Bob coughed. "Casey?"
"What will we tell our family?"

"The truth to a point. That we are hiding you as a couple. That you will be posing as newly weds. That they should talk about you as though you are married."
"But not that it's actually real?" Casey asked.

Which was right about when Derek realised that she was going to do it.