All teenagers think they are invincible. The children of super heroes doubly so. They grow up in a world where their mummy or daddy really is the most powerful or the strongest, the fastest. Whatever.

They themselves are taught hand to hand combat at fourteen. School fights cause burnt out rooms and broken walls. Popularity is dependent not on looks, money or intelligence, but on power. Strength is key.

This perhaps is why they are unable to comprehend this thing which has shattered their perfect world. Heroes are meant to bring up baby heroes, retire and dandle grandbaby heroes on their knee; or to die at thirty locked in mortal combat with their villainous counterparts. They are not supposed to die at seventeen when their best friend wraps his car around a tree. Not heroes.

Teenagers all think they are invincible. Adolescent heroes know it. That is their downfall.

The whispers run through the school. Freshmen earn death glares for breathing too loudly – and in a school for superheroes that is no metaphor. The rumours had begun the previous night, rocking the small community to its core, but somehow no one believed it was true. Not until steely, composed Principal Powers entered the assembly room in tears. Not until she choked out the announcement.

Death leaves behind not a vacuum, but a fountain throwing out a sort of dark silence that chokes words. The only sounds in the school today are muffled sobs. Everyone steers clear of the school's half dozen or so empaths.

Eventually a new day dawns for the school. Laughter creeps back. The halls are filled with chatter again. But things have changed. People are different.

Warren Peace has known for many years that all things come to an end. Most of his classmates had avoided learning that hardest lesson. Now they know.

No one is invincible. Not even heroes.

A/N: memento mori is a Latin phrase meaning, roughly, 'remember that you are mortal'. It is a common theme in art, where this idea is often represented as an hour glass or skull. I first came across the phrase in a Dr Who fic, where it was used to describe the doctor's relationship with his companions.