‘You may want to put that on now.’ Sam’s father pointed at his jacket. 

A second later, the lift door slid open and an arctic blast of air rushed in carrying thick snow, whipping and swirling around them. 

Sam stood dumbstruck staring out at the high white mountains before them, whilst his father zipped his coat up to his chin and stuffed his arms into deep pockets. 

‘Come on.’ Frost was already forming on his glasses. ‘Stay behind me and – whatever you do – don’t turn around!’ 

Despite the brief blast of snowy air, none appeared to be falling on the mountain, which glistened under the starry sky. Ignoring the only piece of advice he had been given, Sam turned around and nearly suffered a heart attack. 

There was no lift behind him. 

No door. 

In fact, there was nothing behind him. Well, not for several thousand feet at least, for two strides away, the ground vanished into darkness.