Eren's 15 and he's in awe.

Never before has he seen anyone so adept and agile, gliding through the air with such control. The first time Eren saw the heichou slice through a titan's neck so seamlessly was the last time he'd ever underestimate someone shorter than him. It was all too easy to cower before humanity's strongest soldier and Eren had been tempted to more times than he could count – especially after the showdown in the courtroom – but time wore on and the fear wore off. Under the heichou's command, Eren began to relinquish his doubts about the man.

Eren's 16 and he's confused.

Had his heart always been hammering this hard every time Levi looked his way? He's not even sure how it had come to this. Last year, every time the heichou neared him, he'd react in a jumpy manner – now, it was for an entirely different reason. Eren hopes against all odds that Levi mistakes his reddened cheeks for a sunburn or overexertion. Besides, Levi is twice his age and has no time for teenagers confused over their sexuality.

Eren's 17 and this time he's sure.

It's been over a year and his pulse still quickens at the sight of Levi, even the mentioning of his name. Eren's learned to tame his nervousness, but he's pretty sure Hanji's got it all figured out – nothing gets past her. She waggles her eyebrows at him behind Levi's back and occasionally makes obscene gestures, yet it's with good intentions. Eren knows he's got no chance, but it's nice of her to play along.

Eren's 18 and he's grown bolder.

He's somewhat of a romantic, though not entirely creative, so he settles for flowers. A single red rose is his gift of choice, and he sneaks into Levi's room to place it on his desk the day before a mission. In a way, it's like his version of a good luck charm – a silent way of saying "come back alive so that I may have the chance to tell you how I feel." Each time Levi lives and each time Eren can't muster up the courage, so it becomes a sort of unsaid tradition. A rose, a mission, another unspoken confession.

Eren's 19 and he's still trying.

Where do the roses even go? Does he throw them away without a second thought? Eren examined Levi's room once and not a trace could be found of the roses – not even a petal. And yet, wounded but persistent, Eren continues. At times he considers confessing personally to Levi, face-to-face and with words, but he's sure he's only setting himself up for heartbreak. Best to live in the illusion. What would Mikasa think anyway?

Eren's 20 and his heart has shattered.

Eren falls to his knees, gathering the heichou's broken, barely-breathing body. What happened to the roses' charm? Wasn't it infallible? Humanity's strongest soldier wasn't meant to be lying on the forest floor, bloodied and bruised and limp in Eren's arms. Eren can't stop his tears, but what's worse is he can't stop Levi from slipping away. He's lost all self-control and the words I love you slip past his lips without permission, finally free after years of restraint. He watches helplessly as Levi, in his final moments, meets his gaze and weakly pulls back his jacket to reveal the rose Eren had left on his desk only the day before, tucked away securely inside.

Eren returns to bury their beloved heichou, heart thudding hollowly in his chest, and finally discovers where all the missing roses went. As he kneels in the graveyard, his gaze sweeps over the headstones of Levi's squad who had sacrificed their lives for him 5 years earlier – and there, spread between the four graves, are the roses. Having lived past each mission, Levi had been passing each flower – each good luck charm – to each of his former squadmates. A show of respect, of gratitude – a thank you for keeping Eren alive.