One of the world's most vertical cities is plunged into chaos if people can't trust elevators how will they cope?

This claustrophobic scenario is brimming with suspense and intrigue. The tension is palpable in opening chapters, you just know something terrible is going to happen and are instantly fearing for the characters.

The short chapters help ensure it stays fast-paced and only helps to racks up the tension, as you try a work out who this ruthless killer is, as the death toll increases. Pact with twists and turns that finale is breathtakingly shocking. Even if you guess the killer (on this occasion I did) the unveiling of his deadly plans motives are jaw-dropping.

A terrifying premise with all the with so much possibility to be a reality it makes you think twice before you step in the elevator. Barclay is a master at his craft. If you are looking for an intense thrill, look no further you have found it!

Thanks to HQ Stories & Netgalley for sending me this in exchange for an open and honest review.