As a little boy, his mother used to tell him that life was like a waterfall trying to fit inside a glass. At some point, the overflow was inevitable.
He was already full to the brim.
Therefore, when he stumbled across an invisible barrier, right in the middle of the worn out floor of Compartment I, it was just too much.
Later on, much later, he would wonder if it had been fate that led him to what was, no doubt, the rashest decision of his life. The right circumstances, that one single drop enough for the glass to spill.
As it was, after his feet collided with what appeared to be solid air, it had taken only a glance at the empty space in front of him to know. He had found him.
If he hadn't been so lost in thoughts, the dark crimson stain slowly spreading across the flooring should have been a telltale sign of the other wizard's presence. But such was that, when he rushed forward and scrambled to rip away the invisibility cloak and found himself staring into green, he was still utterly unprepared.
Sprawled across the shabby carpet of the last carriage of the Hogwarts Express, he lay motionless, but for the frantic quivering of his irises, the only indication he was still alive.
Dried blood caked his left cheek, tilted towards the floor. A stark trail of bright red stood out against his clammy skin, starting at the tip of his nose and accumulating in a lone bead just below his ear. He watched as the droplet filled, following the tug of gravity towards the sticky pool that drenched the boy's hair and the carpet.
He could recognise the plea in the boy's eyes, the growing confusion about why he hadn't been released from the spell yet. Despite that, he couldn't help stalling, lost in a sea of familiar memories. He took his time cataloguing each feature, each nod to the past.
It was like coming home.
He dropped to his knees, gently supporting the lean body in his arms and just let himself look.
The unruly hair, ink against pale skin, just a hint of dotted freckles across the bridge of his broken nose. The slight asymmetry of his upper lip, fuller on the right. He was taller now, while still somewhat too skinny, his body had stretched over half a foot during summer, catching up with the distinguished height of the Potter's lineage. He was almost a man, yet still a child. So goddamn young. Each trait a stabbing reminder of whom had once been just as young, just as lively.
But it was the eyes that did it. In Harry's green irises there was nothing of the carefree light that had once gleamed in sixteen years old Lily Evan's ones.
And it felt like failure.
The unfairness of Harry's life hit him like a bludger, the urge to protect overwhelming.
In that single moment, lain across the rundown floor of the same train that had once taken Harry to the beginning of his new life, fate offered him one simple solution.
With a quick wave of his wand he watched as abused cartilage straightened, blood and dirt vanished, leaving no traces of what had happened behind.
He was running out of time. The "Finite" falling from his lips sounded like an apology. A prayer.
Please, forgive me.
Harry blinked, his face and body relaxing. He smiled tentatively, huffing out a breath of relief.
"Hi. Thanks, I -"
He was running out of time.
Please, forgive me.
His next spell sounded nothing like redemption, yet he still hoped it would be the right choice.
"Obliviscere".
There was no going back.
So, when a wisp of silvery smoke morphed into a phoenix, right before him, asking in Dumbledore's grave voice, "Have you found him?", his responding denial was resolute and confident.
Later on, much later, he would tell himself it was fate that had led him to the rashest decision of his life. Anything to quell the doubts and guilt weighing heavily in his chest.
In that moment, one glimpse at Harry, looking lost and still too addled to even notice the Patronus, was all it took.
He grabbed the younger wizard's arm and apparated them away.
There was no going back.