“Someone else is out there, watching, waiting. Terrorising us.”

Lina is an ambulance driver, dealing with emergencies for a living. She is also dealing with Cain, her husband of seven years, who is still having nightmares after returning injured from serving in Afghanistan. Lina worries about money and about her marriage. Cain wants easy money not “a boring job”. Lina agrees to his easy-money scheme of renting out her family lakehouse at Tarawera via the WeStay app. Lina uses another kind of app. to take desperate measures to save her marriage …

Cain’s injuries were sustained during a botched special forces raid. He and his mate Axel were to testify at the enquiry, until the man facing charges – their comrade, Trent – committed suicide. Cain was seen as a hero, until the enquiry put a shadow over his tour. He has turned to gambling in the past to make money when his personal-trainer business failed to take off. And Lina fears that’s what he is doing again. He wants to be a hero again. He wants to be her saviour.

Lina spends her life proving she is not like her alcoholic mother, “I’m nothing like her”. She was raised by her grandparents in the lakehouse, and carries her memories, both good and bad “Mum turning up, eyes bloodshot, haggard. The screaming. Grandma sweeping up the broken glass”. She is also haunted by a miscarriage she had when she and Cain lived at the lakehouse. She knows a baby will give her a chance to prove she is not her mother. And will give Cain purpose, a reason to move on from the war.

When they list the lakehouse, Lina and Cain engage in ‘innocent’ online stalking of potential renters – finding how easy it is to see their personal details. They have sex, both enjoying imagining Lina is one of their guests. The reader already knows there is a far more sinister form of surveillance going on in WeStay houses – and Lina finds out the hard way, when she visits a WeStay property in Auckland. She ends up being pursued by someone, someone who has information that could ruin her marriage. They also, symbolically, have her heirloom wedding ring.

Lina and the reader end up suspecting everyone, even those trying to help. She falls into a nightmare of demanding honesty from Cain – and getting more than she bargained for – while keeping secrets from him. She thinks all her decisions are for the best, but many come back to damage her. Her medical training (she was in med. school before dropping out to be a paramedic) means she is inured to death and injury similar to the way Cain is – “Soldiers being blooded by killing prisoners. You’re never the same, I’ll never be the same.”

“Even the best photos of the view miss the smell, the air” – the lakehouse is idyllic, but turns to a house of horror for Lina. She is put in extreme danger but gets help from a very strange source. And she, not Cain, ends up the hero. In the aftermath they have to suffer journalists and interviewers. The media is not out for truth, but for click-bait and public attention. Cain and Lina see the ‘good bloke defence’ potentially obscuring the crime. Then when Axel and his wife Claire travel with them to the lakehouse, Lina starts to realise the nightmare might not be over. She still has some big decisions to make. “Everything is wrong.” What decision will make their world right?

The last guests is a gripping thriller in a world where ease of surveillance has lead to voyeurism being a commodity, and where a dulling pragmatism leads to people doing extreme things to secure their ideal lives. It is a tense read, and the reader is guessing the whole way through. Lina is a complex and interesting character – who makes morally ambiguous choices. Excellent!