Spring
"A History of Magic" story, it is compliant with the series generally but from Snape's point of view. The beginning of the story reflects what I think was intended by the "lapdog" comment in OotP, if you are skeptical.
Chapter One
He thought the note was a joke at first; was the old man completely out of his mind?
Severus tucked the note into a chest pocket, pushed his hair back out of his face, slicking it against his skull and re-examined the set-up, a finger lightly checking the security of valves and joints, aware that Lucius was watching him from the doorway.
"What do they want, Severus, are you missing credits and you'll have to return for another term?"
Severus ignored him which only brought Lucius back down the steps to lean over his shoulder, unbearably, into his personal space. Severus, as scripted, took his elbow and started pushing him away as though Lucius were a child.
Lucius laughed and backed up until he arrived at the chair and sat down, continuing to watch him. "Really, Severus, why are you getting letters from Hogwarts? Did they offer you a job?"
He still couldn't be bothered to respond and instead he tightened a washer with his wand. "Lucius, please, why don't you summon tea, I've been working so hard all afternoon."
"If I'm going to fetch your tea, I want to know what the letter said," summoning tea. He readjusted his position in the chair and began to eat a sandwich poking a stray cucumber back between the slices of bread with a finger.
Severus turned away from the distillation equipment and raised an eyebrow.
"You've been practicing that in the mirror, feign to deny it."
Severus glowered. "The note said that two others had been destroyed because someone other than myself tried to open them."
"Yes, that was me, of course. Look, they send you a letter to my home; I want to know what is in it."
Severus sat down beside Lucius and took the tea he was offered.
"Nothing, the old man is crazy. He invited me back for dinner. He thinks he can save me."
"Did he write that? Exactly that?"
"What?"
"That he can save you?"
"Of course not. What would he invite me back for? The pleasure of my company?"
Lucius snorted. "Don't tell the Dark Lord you are getting letters from the old man." Lucius paused. "What kind of dinner? How peculiar. Didn't he want you dead? Perhaps he wants to poison you, rather than save you. It would be closer to type."
Narcissa had entered the room and took a cup of tea proffered by her husband, smiling at Severus who was scowling at Lucius.
"Why are you torturing Severus, dear, our guest looks so unhappy." She sipped her tea and tugged gently on Severus' ear, standing behind him. "What are you discussing and who wants to kill Sev? Is this about my cousin?" She bent over his head and sniffed his hair, tugging on a lanky clump.
"Noo" Severus drew out the "o" in an exasperated whine. "Is this trip down memory lane really necessary?" He took a sip of tea. "The old man wants to congratulate me for becoming a Master and invited me to a private dinner. He probably does it for all such achievements by former students and he probably would take the opportunity to kill me. I'm nothing to him but a Potions Master in the service of the Dark Lord would be a worthwhile kill.
I'm not going, obviously…" Severus had omitted the fact that he had been invited to be Air for the Spring Equinox ceremony besides the dinner, that wasn't actually for him. This was, frankly, an unimaginable honor and his silence was in keeping with the tradition. He was compelled not to speak about it by the goddess, Eostre, herself. He might not go for the dinner, but he was sure as hell going to the ceremony.
"I wouldn't let him kill you."
"Thank you Lucius."
"Maybe you should tell the Dark Lord about it, you could do reconnaissance. Perhaps if you killed the old man for him..." She tweaked Severus' ear and he batted her hand away.
"Stop groping Severus, you're making me jealous. And bless him, he is disgustingly talented, but he'd never even be able to pull his wand on Dumbledore."
"Hmmm." Narcissa acknowledged the last statement with an affectionate smile for them both and again squeezed on his ear.
"I have ears, too, you know."
Narcissa and Severus looked at Lucius and Severus gave an apologetic shrug which caused them all to laugh.
Narcissa rose and pulled Lucius out of his seat. "Come dear, let the half-blood Prince work..." She started up the small stair and out the door.
Lucius turned to Severus, "Don't tell the Dark Lord about the invitation. I'm jealous of your achievement and the favor he has shown you. I tell everyone how much I supported you on the journey, but this isn't about slytherin strategy. You haven't really proved your worth to him yet and you need to be an asset alive, not sacrificed for sport. "
Severus merely nodded gravely. Lucius patted him on the back and followed his wife up the stairs.