From the author of the #1 Bestselling Audible Thriller of the Year comes a terrifying high stakes hunt to the death...

It is the winter solstice, the longest night of the year.

When a New York Senator is chosen as an assassination target by Colosseum, the chilling online game, she faces a terrible choice; to run or to hide.

No-where is safe. No-one can be trusted.

But just when the Senator’s brutal death seems inevitable, a young agent arrives from London to protect her. Now Winter is all that stands between the Senator and Colosseum's deadly hunt. As dawn creeps in, time is running out for Winter to unravel the mystery at the heart of this sinister game: who is the shadowy head of Colosseum, and what is his ultimate purpose?

It is darkest before the dawn.

As Winter and the Senator journey together into the dark heart of the longest night, they soon discover that nothing about Colosseum is what it seems. There are rules, and there is a purpose, if only they can solve the riddle in time. Colosseum is more than a hunt: it’s a challenge.

Targets must face their darkest fear, or die at dawn.

'Callister's experience as a City analyst of tech companies has alerted her to the dark side of the information revolution. “The internet has facilitated the maximum realisation of human nature,” she says. And she is not talking about random acts of kindness or a fondness for cat videos. “If you want to do weird stuff, no matter how extreme, then the internet can connect you to someone in New Zealand (or wherever) who wants it too. These are people who should never meet.' The novels are dystopian adventures in the surveillance society, featuring what she calls “toxic femininity”.... It’s probably the most direct riposte to Harvey Weinstein yet.' The Independent