It's the end of the chase. The truth about Helezon and the Sky Machine is revealed, and it's one that transcends any conspiracy about climate engineering. When David returns to Orkney to find Susan, what will he have learned, and what will that knowledge lead him to?

Susan has given David the time and opportunity he needs to discover the meaning of her brother's last message. But the sky machine proves to be more than either of them expected. And now David has an appointment with one of the figures behind Helezon. It will be a dangerous encounter, held in a strange forest of metal trees, in a place that feels like nowhere.

Susan has found David, and she has a lot to tell him. But how much of it will he want to hear?

David and Susan are separated. David is in the hands of their pursuers, but what is it that they want? As he faces a strange interrogation, he must find courage from somewhere. He can try to hold out, but that's going to be difficult when a small amphibian is involved.

A small community centre and cafe by a Scottish loch offers David and Susan an oasis of calm as they travel back to London. But a strange conversation with another customer may alter their plans dramatically.

Orkney offers a few days of peace and reflection for David and Susan. But the ever-present threat of Helezon and strange links with the islands' Neolithic history combine to shatter their hopes and remind them of the dangers they still face.

In an attempt to regain access to the ROC, David and Susan arrange a meeting with a fellow-scientist in Amsterdam to persuade her that they have not been sucked into a mad conspiracy theory. Maybe it will make things feel more normal, for a while. But what has happened to the paintings in the Rijksmuseum? 

David and Susan try to behave normally, despite the growing danger. But when Susan receives a message from a contact, their field trip to a climate research station takes a sudden and dramatic turn. Who would have thought that time could be so deadly?

A young scientist attempts to persuade a colleague that she has stumbled on information that is putting them in danger. Cut off from the academic community and branded a conspiracy theorist, can she convince him that governments are working to deliberately alter the climate for their own ends? And what is the meaning of the strange text message she has received from her brother? 

Cloud formation specialist David Forrester is stuck in a garage. He's frightened, and for good reason. But what could have got a rational, sceptical climatologist into a situation where he fears for his life?