Evenin' all.

We all step near the line at one time or another, but few cross it. Tonight's episode is about what happens when the line is crossed.

* * *

Reet looks at me strangely. She knows where I'm going. Today is a special day. It's two years ago exactly since it happened.

* * *

"My husband's having an affair," said Mrs Nash.

Private investigators hear this sort of thing all the time. I let her carry on talking.

"He's been sleeping with Kristina, a Croatian refugee, we took in," she - Sarah, let's call her Sarah - continued. "She's going home now. He's taking her to the airport. I want you to see that he doesn't go with her."

"Are you sure you want to know?" I ask. People often don't really want to know the truth.

* * *

What if she had said no? Where would we all be now? I laid the flowers on Robert Nash's grave. Have you any words for me Rob? Silence. I'm good at silence. I said nothing to my mum when I discovered my father was having an affair.

* * *

I reached Kristina's flat in Fulham shortly after 4pm. The two of them left the flat at about 5pm, got into his black Saab and proceeded in a westerly direction down the M4. They turned off at the Heathrow spur and parked at terminal 2. Kristina walked through the departure gate, without looking back.

* * *

They treat me differently at the prison. They know I'm an ex-police officer. They think I'm corrupt, but all I was trying to do was nail that bastard Dyson. I knew he was guilty. So did everyone else, but we didn't have the evidence so it was my head on the block. My wife, Rachel, left me soon after. Any excuse.

The doors open and I walk into the visiting-room. She's sitting down already. "Hello, sweetheart," I say. "I'll be waiting for you when you get out."

* * *

I don't know why I decided to follow him home. Would anything different have happened if I hadn't? Maybe she wouldn't have seen what I had seen. And I wouldn't have been able to write this book. Nor you to read it. So much rests on our choices.

I had seen the emptiness in his eyes. He had gone back to their house in Wimbledon but his heart was on the plane. Sarah had been cooking him supper when she saw those eyes. So she stabbed him to death.

* * *

I return to my office. Reet had told me it would fade. But it hasn't. One day I won't be a visitor any more. And I won't return alone.

So remember folks: Wimbledon is still very safe; unless you cross the line. Mind how you go, now.

The digested read ... digested

The quantum theory of suburbia