Little Emma Stonebridge had lived for one day. Kate had haemorrhaged so badly after the birth that they thought they would lose her too. But she survived, coming out of it minus her torn and damaged womb. The shock of losing Emma before she could even hold her, and then discovering that she could bear no more children, had pushed her one heartbreak too far. It had been a long road back for them both.

Matt and Liz knew the bare bones of what had happened, but Will had never gone into detail about the full extent of Kate’s emotional disorder.

Now Kate seemed to be operating in overdrive, working all night in her studio and decorating by day. She accomplished miracles. Along with her reluctant workhorse, Will, she painted and papered, bringing the old house back to its former splendour. Will’s more relaxed routine long abandoned, she even found time for longer walks on the marshes and the sea bank, sometimes disappearing for hours at a time. Will could only watch in horror, waiting for the inevitable crash.

On this particular day he was carrying some empty paint cans to the garage when he heard someone call out to him.

‘Sorry to bother you, Mr Stonebridge. Have you got a moment, sir?’ Barry’s foreman, an older man called Neville, was coming towards him along the drive.

As he went out to meet him, Will experienced an odd disquiet. His gut began to churn, as it had when he was still in the force, a sure sign that something was not right.

‘You know that natural bit of higher ground behind the well — the mound we cleared last week and planned on cutting the terraces out of?’

Will nodded.

‘It’s not actually natural at all, sir. It’s an old air-raid shelter, left over from the war. We don’t rightly know what to do now, sir. Would you come and take a look at it?’

He and Kate had often wondered about that piece of raised ground. Lincolnshire gardens were predominantly flat. In the end they had decided that it must just be old topsoil piled up and ready for a job that never got done. Weeds and brambles had covered it completely.

‘Well, I’m damned!’

‘It’s built a bit like an Anderson shelter, dug down into the ground and with them curved sheets of corrugated iron over the top. I remember playing in the one my gran had — she lived in the East End of London during the blitz and used her shelter as a sort of garden shed for donkey’s years. Good fun for a kid, too. My brothers and I used to love it.’ Neville chuckled.

‘I am surprised there’s one on the fens,’ Will said. ‘London certainly, but out here?’