I saw my neighbor’s wife holding hands with another man. But he wasn’t a secret boyfriend—he was her husband’s identical twin. Then I learned the family secret behind him.

I couldn’t believe what I was hearing.

I had lived next door to Mark for almost six years.

He seemed like the nicest man imaginable.

“What did you do?”

“I asked him to explain.”

“And?”

“He gave me this.”

She placed an envelope on the table.

Inside was an old photograph.

It showed Mark and Michael as teenagers.

But written on the back was a date.

And beneath it, four words:

“Ask him about the fire.”

I stared at her.

“What fire?”

She shook her head.

“I don’t know.”

Then she looked directly at me.

“But Michael said Mark had lied about what happened twelve years ago.”

I left the coffee shop more confused than ever.

That evening, I saw Mark outside his house.

He waved.

“Everything okay?”

I forced a smile.

“Yeah. Just tired.”

He smiled back.

But something about him suddenly felt different.

That night, I barely slept.

The next morning, there was a knock on my door.