The Potions Master and the Ravenclaw

Protego Diabolica

It was lunch time and Snape and Madeline entered the Great Hall. They made their way up to the staff table and sat down together, McGonagall on Snape's left and Madam Hooch next to Madeline.

Madeline spooned some shepherd's pie onto Snape's plate and placed it in front him before selecting some fruit and cheese for herself.

"You'll spoil him, Madeline," said McGonagall. "Once you start that, you'll have to keep it up forever."

"I don't mind spoiling him. I rather enjoy it," said Madeline, laughing.

"Leave her alone, Minerva," said Snape, smirking. "She's doing just fine without your help, I thank you very much."

They all laughed.

At that moment, Madeline noticed Mad Eye Moody enter through the side door and sit at the end of the table. Snape glared at him for a moment before turning back to his plate. Then Madeline became aware that the ex-auror was staring at her with his magical eye. 

Madeline turned to Snape. "Severus, why is he staring at me? I feel as though he can see through my clothes." She shivered.

A murderous expression fixed itself across his features as his eyes locked onto Moody and he started to rise from his chair. Madeline pulled him back down.

"Severus, no. Please. Don't start trouble."

"I'm not starting it. I'm finishing it. I'll be damned if I'll allow him to harass my wife."

"Please. Let it go."

McGonagall laid a calming hand on his arm. "Don't let him rankle you, Severus. I really must  talk to Dumbledore about reigning him in. You know he transfigured Draco Malfoy into a ferret last week."

"He did what?" Snape was incredulous.

"I reversed the spell immediately, of course, and I told Moody that we never use transfiguration as a punishment, but I'm not sure it sunk in.  Though, to be honest, I wasn't sure whether to be appalled or amused."

"Wait until Lucius hears about this. He'll be livid," Madeline interjected.

"Indeed," said Snape. "And Madeline, you are not to be alone with Moody. Do you understand me?"

She nodded.

He reached for her hand under the table and squeezed it.  He would definitely have to keep an eye on Mad Eye Moody.

...

The next morning, Snape's mark had grown even darker. He had stopped panicking by now, long since resigned to the fact that the Dark Lord was obviously gaining strength and would somehow return, though no one could predict when. He had used his power of occlumency to control his fear and apprehension and had adopted a sort of dark resolve and acceptance regarding the matter. However, every time he looked at his beautiful young wife his steadfast commitment to protect her by any means possible intensified. 

After she woke and she had forced him to eat breakfast, he took her to the room of requirement.

"What are we doing here, Severus?"

"I want to teach you something. Something that may protect you. Give me your wand, please."

She handed it to him.

"Black walnut, am I correct?"

"Yes."

"And the core?"

"Dragon heartstring."

"Interesting that this wand chose you, Madeline. Black walnut. Dragon heartstring. Unyielding, by the look of it. What do you know about black walnut wands?" He was using his professor voice.