Disclaimer: I don't own Harry Potter. All rights belong to JK Rowling.
"...Prongs rode again last night." - Albus Dumbledore, OP
"But though Death searched for the third brother for many years, he was never able to find him. It was only when he had attained a great age that the younger brother finally took off the Cloak of Invisibility and gave it to his son" - Tales of Beadle the Bard
Prologue
James Potter listened to the loud bangs and crashes coming from outside the door. They are going deeper into the Shrieking Shack; drawing nearer and nearer to the closed room where James was hiding. He could hear a demented, high-pitched cackle amidst all the racket and it made the tumultuous noises even more ominous. Cousin Bella's up for some muggle-born hunting with her master. He wasn't surprised, though; Bellatrix rarely leaves Voldemort's side especially when it comes to murdering muggle-borns, a pastime they both enjoy. But the idea that Bella was willing – no, eager to murder these people who were in Hogwarts with her, who ate and talked and had classes with her, infuriated James so much that he was almost impatient for the imminent confrontation.
He stood up from the rickety chair he was sitting on and faced the door; his wand on the ready. He needed to keep them distracted, to stall for enough time to let Evans smuggle the others out of the Shack. He would have preferred if a few other Order of the Phoenix members were there to back him up but James wasn't worried; he has escaped from more difficult situations, escaping Voldemort would be a breeze.
His mind went through what happened earlier that day. He was back home with his parents, telling them of his plans of going away and staying permanently with the Order so that he can be more useful to their cause. They didn't take his news well but James knew his parents would never stop him from doing what he wants; all they could do was to try and persuade him against going. James smiled sadly, knowing that he was going to break the hearts of the two people who had loved and took care of him his entire life, and told them that he had quite made up his mind.
A loud and impatient knocking startled them and interrupted their somewhat gloomy têtê-á-têtê. All three instinctively drew out their wands. James rushed towards the living room and opened the door.
Chapter 1: Grim News
Severus Snape was the last person in the world he had expected to see standing on his front porch. He was quite agitated; his long, lank, dark hair disheveled, his hands doubled into fists on his side, clenched so hard the knuckles showed white. He wore his usual dour face, and yet James saw a plea in his black eyes.
"What is it?" James asked, suspending the usual harsh and mocking tone he uses when talking to Snape and opting for a kinder voice upon seeing the other's discomfort. "Is there something you need, Snape?" Snape did not speak. James became suspicious and remembered that he was talking to a suspected Death-Eater.
"Why are you here?" he asked, no longer hiding his disdain. "If you're here to force me into telling where the Order's headquarters are, you should know better. You might as well kill me for I will never be able to tell you where it is, even if I did want to." Still, Snape was silent, staring fixedly on a potted plant in the windowsill, until James became annoyed. "But then, you will never be able to kill me, Snape," he taunted, "You owe me your life."
Snape threw him a scornful look. "I'm not here for your so-called Order," he said scathingly, then hesitated before continuing, "I'm here to tell you that the Dark Lord has plotted another mass murder. He plans to round up as many muggle-borns as he can find." Snape stared at James intently, letting the weight of his words sink in, "Lily's in danger. You have to take her to safety. Hide her, take her away."
James raised his eyebrows sardonically. "What makes you so sure he's going to kill Evans?"
"Are you dumb, Potter?" Snape yelled at him furiously and James felt like they were back at Hogwarts, having their usual, daily run-ins. same old Snivellus. Except there was a certain hint of desperation in Snape's voice, as if he didn't really want to fight back.
"Haven't you figured out that Lily is one of the few muggle-borns who's explicitly defying the Dark Lord by joining Dumbledore's stupid club and fighting against his Death-eaters? Did you think he wasn't going to take it as an insult that a mere muggle-born is able to live freely and even fight him?" Snape continued, "What's more, Lily lives in a village teeming with muggle-borns! The Dark Lord plans to go there at sundown today!"
At this, James' expression turned grim. "How did Voldemort find out where Evans lives?" he asked. When Snape couldn't meet his eyes he seized him by the collar, almost lifting him from the ground and forced him to meet his eyes. "How did Voldemort find out where Lily lives, Snape?" James repeated, struggling to control his fury, "Turned traitor at the littlest prodding from your master, have you? Or was ever-loyal Sev' willing enough, after all, to betray his best friend in exchange for eternal glory?" James' anger threatened to overcome him. He was shaking Snape violently, shouting, "Answer me you bloody coward, answer me!"
Snape tried to free himself from his grasp and fight him, shouting back, "How dare you accuse me, Potter! You know nothing of what I went through to protect her!"
"Well, whatever you did, it wasn't very successful, was it?" James retorted, "You led Voldemort right to her, didn't you?"
Remorse was etched in Snape's pained expression. He looked almost pleadingly at James, as if by making him understand, he could be forgiven for the danger he brought upon Lily Evans' life. "I couldn't help it. I tried; truly, I did. But the Dark Lord is an extremely powerful Legilimens and I have yet to master Occlumency." Controlling his emotions, Snape looked at James squarely and said, "Whatever my failures are, I cannot undo it. I came to you because I knew you will do whatever it takes to save her."
"Why do you even care so much about her? After all, she's just a mere muggle."
It was Snape's turn to grab him from the collar. They glared at each other for a few, tense moments before James spoke, "Alright, if you're so besotted with her why don't you save her yourself?" Snape's grip on his shirt, slackened and he looked away.
"Oh, of course!" James said derisively, "You can't do that without ruining yourself in the eyes of your beloved Dark Lord! You'd incur his terrible wrath! Why die for the only person who ever cared about you, eh Snape?"
Snape wasn't looking at him. He kept his head bowed even as he said, "Just save her, Potter. Take her with you. Hide her where he could never find her." He turned and walked away. "Lily Evans will never turn her back on you," James called out to his retreating back, "yet, you willingly turn your back on her every time you go back to Voldemort!" Snape continued walking and didn't look back. "Stop being a coward, Severus!" He reached the end of the Potters' driveway and, turning, disapparated.