Freya Medlock, a reporter at her local paper, is down on her luck and chasing a break. When she's assigned to cover the death of a young climber named Stephen, she might just have the story she needs. Digging into Stephen's life, Freya uncovers a strange photo uploaded to an urban exploration forum not long before he died. It seems to show a weird nest, yet the caption below suggests there's more to it.

Freya believes this nest - discovering what it really is and where it's hidden - could be the key to understanding the mysteries surrounding Stephen's death.

Soon she meets Shep, a trainee steeplejack with his own secret life. When Shep's not working up chimneys, he's also into urban exploration - undertaking dangerous 'missions' into abandoned and restricted sites. As Shep draws Freya deeper into the urbex scene, the circumstances of Stephen's death become increasingly unsettling - and Freya finds herself risking more and more to get the answers she wants.

But neither Freya nor Shep realise that some dark corners are better left unlit.