They clutched their pink balloons and swayed happily to the songs, taking selfies, as the music thumped - cramming everything into the moment, as young people should.
At the same time, a person walked towards the concert in Manchester - determined to create as much damage as possible. What was he thinking as he walked through the night, knowing what he was about to do?
Parents waiting outside the venue to collect their child craning their necks to catch a glimpse of their son or daughter, mothers at home glancing at the clock - the low hum of worry never out of their minds. They'll be home soon.
But many won't. Because of a moment, a dark thought, a misguided journey - so many have been robbed of so much.
Friends died side by side last night, fathers left unable to protect daughters, and innocence forever shattered.
One of the last acts of the attacker was packing his explosives with bolts and nails. It is believed the impact sent them flying like bullets, designed to hurt as many people as possible. The majority of the victims, teenage girls.
The aftermath of any atrocity is deeply disturbing - but the pictures from last night of the emergency services working on these injured children or watching their parents being hurt won't leave our minds.
Their achingly sweet Ariana Grande t-shirts, their bewildered, frightened faces - their ripped jeans being ripped away by paramedics, a sea of burst pink balloons on the floor stamped to death by panicked feet. Their happy memories collapse around them, smashed by hate. I'm so sorry this world could not have kept you safer.
This is every parent's nightmare - the most wretched parts of the world colliding with the innocence of young people out having fun. This is the thing that quickens our pulse and prevents us from sleeping. We reassure ourselves, this could never happen to us, to our child. But today, for many, it has.
Which is why the tragic deaths of so many young people and their loved ones in this attack echoes through the deepest core of every parent's heart. We are living the agony of every mum and dad that are suffering a loss today in Manchester.
And that has a much further reach than bolts and nails.
(Written by Amanda Cassidy, Editor MummyPages Life)