A/N: Alas, I own nothing of Narnia. I wish I did.
Most of Edmund's scars – the worst ones at least – were mental, some of them self-inflicted. The majority of his battle-wounds – the worst ones, at least – were healed by Lucy's cordial. The others he managed to keep hidden, in this unmagical world – all but the very worst one.
He'd being doing well, and they might never have known, had it not been for the mugger when he was in his teens. In actual fact, the mugger had come off a lot worse than he had (well, he hadn't been expecting to come up against a King of Narnia who'd fought in more combats than you could wave a sword at, and who was no stranger to self-defence and hand-to-hand fighting, so that was hardly surprising), but he'd still ended up with a split lip, bloody nose, black eye, and, he suspected, a couple of cracked ribs. He limped home, managed to avoid his parents, and went to find Lucy.
Not that Lucy had her cordial here, and maybe, in a land that wasn't magical, like Narnia, it wouldn't have worked even if she had, but she'd become accustomed to the 'normal' sort of healing when she was in Narnia; she knew how to apply poultices and wash wounds and, most importantly, wrap cracked ribs. She winced in sympathy as she pressed softly and he hissed in pain. "Sorry."
"'S okay," he said with effort.
"Take your shirt off, I'll have to sneak downstairs for bandages."
It was unfortunate that, although soft-footed Lucy hadn't been discovered, his parents had decided on an early night, had come upstairs, and, seeing Lucy's door open and light on, popped their heads in to bid her a good night.
His mother had fussed and flapped, and had wanted to call the police; his father had remained silent, concerned. She insisted on helping Lucy when she returned with the first aid kit, scolding them both for not telling her. They'd cleaned up his face, and set about his ribs. It was then she noticed the scar.
"Good grief, Edmund, what on earth did he do to you?" she exclaimed, staring at it in horror.
His father, drawn by the commotion, took a closer look, and reached out a finger to touch it lightly. Neither understanding nor questioning how it got there, but recognising it for the battle scar it was (he'd seen scars on countless others in the war; he knew a thing or two about them), he said, in his quiet way, "that's an old scar, dear. Not worth bothering about now. Let's just get his ribs wrapped and let him get some rest." He gave Edmund an unfathomable look, and left the room, beckoning his wife to follow him when it was obvious that Lucy was perfectly capable of wrapping the ribs on her own.
Both teenagers let out shaky breaths. "He suspects something," Edmund said morosely.
"Of course he does. He's not stupid," muttered Lucy. She couldn't help but avoid touching or looking at the scar that even her cordial could not completely heal.
It is this scar that Susan stares at in horror when she identifies the bodies, the sight of it – usually hidden from view – rips open her own never-quite-healed scar of seeing her baby brother dying in agony, stabbed with the wand of a vicious, icy queen.
She, too, has scars that will not heal.