Diana Bakewell is London’s savviest and best connected tour guide. As the lead guide at Chartwell and Crouch Tours, she’s busy teaching her young assistant Zaf the ropes alongside dealing with company politics and her slimy boss. In her spare time she’s helping Zaf find his feet in London and coming to terms with the fact that a tabby cat called Gus has stowed away on her vintage tour bus. But when Diana and Zaf take a group of students on a tour of the Houses of Parliament and an MP's researcher dies, Diana suspects all is not as it seems.

Zoe has to hit the ground running. She needs to manage a new team with its fair share of challenges, get to grips with a new boss who might not be all she seems, and worry about her reputation following her north to Cumbria. Can she settle in quickly enough to solve the murder and quell local tensions, as well as coping with an unfamiliar environment?

Detective Lauren Pengelly has only been part of the Penzance police force for less than two years, but that’s enough time to know that the sleepy Cornish town doesn’t see many murders. So, when the bones of a woman with a hole in her skull are discovered behind a derelict cottage, she immediately assumes the worst. Rallying her team, Lauren is flooded with a strange sense of relief when the bones turn out to be almost twenty years old, not a recent victim. But it quickly turns to dread when she receives her second heart-stopping call of the day–a little girl, Isla, has been kidnapped.

When America's newest internet billionaire is shot on the shores of Loch Lomond, the team is brought in. Jade suspects a connection with the shooting of a local millionaire, an unsolved case which has been haunting her. But the team has its problems. Jade is only just back at work after a personal trauma, and can barely leave her own front drive. Petra is receiving anonymous phone calls and trying to establish a relationship with the latest in a string of girlfriends. And Mo is missing the city and his old boss DI Zoe Finch.

Detective Chief Inspector Harry Grimm is forced to take leave from Bristol’s Major Investigations Team when his boss, tired of Harry chasing the ghost of his murderous father, sends him north on secondment. Used to city life and high stress, Harry fears his life will now be spent handing out speeding tickets, finding lost sheep, and directing tourists. But when a local teenager runs away, Harry finds himself pulled into an investigation much worse than anyone could have ever expected.