They sat in the end booth of the diner, the one furthest from the door. He still wore his hat and her, her coat.
“It’s just awful isn’t it? What happened to Howard.” She looked out the window at the darkened street outside.
“It always is, when someone is murdered.”
The waitress came over and gave them their coffee. She thanked the waitress, but remained unmoved. The only other occupant of the diner was a man eating pie at the other end of the counter.
“What were you doing on the eighth anyways?” he asked her.
She opened up a packet of sugar and poured it into her coffee. “I was in my aparment all night. My cat was sick and I had to take care of her. She’s just so dear to me you know.” She took a sip. His coffee remained untouched.
“And let me guess. Because of this you didn’t see anyone, and nobody saw you. And your cat was better by morning so that there was no need to take it to the vet, and no way for anyone to know how sick that cat really was.”
She only looked at him.

That won’t do for an opening, will it?
It doesn’t give you any real sense of the characters and how they’re feeling. I need to show that the questions are making Mary (I didn’t even mention that her name was Mary!) nervous. Have her shaking the cup as she picks it up or having trouble opening the sugar.
And the way they talk about the deceased is rather blunt and unnatural. Maybe if Mary questions him about how it happened.
And do I need to mention that the man at the counter is eating pie? Do I need him at all? To recall Chekhov’s gun, “remove everything that has no relevance to the story.” Better to get rid of him altogether.
There’s also much to improve in the way of phrasing and superfluous words to remove. Hell, I even misspelt ‘apartment’.
I’ll simply have to write it again.

They sat in the end booth of the diner. He still wore his hat and Mary her coat.
“It’s just awful isn’t it? What happened to Howard.” Mary looked out the window into the darkened street. “How did it happen?” she asked without turning back to him.
“He was poisoned.” He stared straight across the table at her.
The waitress came over with their coffee. Mary thanked her and he said nothing. The waitress went into the kitchen, leaving them alone in the diner.
“What were you doing on the eighth anyway?” he asked.
She struggled to open a pack of sugar, unable to get enough of a grip to tear it open.
“I was in my apartment all night. My cat was sick, and I had to take care of her.” Finally getting the sugar open. “She’s very dear to me you know.” The mug shook in her hand as she drank from it, coffee nearly spilling over the side. He picked up his coffee.
“And let me guess. Because of this you didn’t see anyone and nobody saw you. And your cat was fine by morning so there was no reason to take it to the vet, and no way for anyone to know how sick the cat really was.”
She only looked at him.

Though better, it’s still far from anything good. It can be worded better and he isn’t supposed to touch his coffee yet, I don’t know why it says he did.
I’ll have to come back to it some other time, but let’s continue with the narrative for now.

She brought the cup down from her mouth and put it on the table. All her strength seemed to have left her.
“Just because no one saw it, doesn’t mean it didn’t happen.” Her voice was breaking.
“And just because you said it happened, doesn’t mean it did.”
He looked straight at her. She turned and looked out into the street to avoid his gaze.
“What do you know about Howard’s murder?” His coffee remained untouched.
“Do you really think I had something to do with it?” Her eyes were lost in the darkness outside.
“No. I know you had nothing to do with the murder. The author is just trying to throw off the reader. The way you can’t hold your coffee still and had trouble with the sugar packet, they’re just details to show that you’re hiding something. But it’s unrelated to the murder as the reader will eventually find out…”

What the hell was that? He wasn’t supposed to say that, nor was he supposed to know it.
It’ll have to be redone.

She brought the cup down from her mouth and put it on the table. All her strength seemed to have left her.
“What happened to that man at the counter that was eating the pie? Where did he go?” Her voice was breaking.
“The author got rid of him.”
He looked straight at her. She turned and looked out into the street to avoid his gaze.
“Apparently he didn’t serve the story. Something to do with Chekhov’s gun.” His coffee remained untouched.
“I think it’s awfully mean to just get rid of someone because they don’t immediately impact the narrative. And doesn’t the author know that Hemingway valued inconsequential details like that?” Her eyes were lost in the darkness outside.
“I suppose they must if you mentioned it. But I think it has become rather clear that the author has lost control of this story. I mean, just look at this conversation. This isn’t what we’re supposed to say…”

He’s right, but there is no need to point it out. But why is he? It’s not what I’m trying to write. Am I really just going mad?
Maybe if I were to do it again it would turn out like it’s supposed to. What other choice do I have?

She brought the cup down from her mouth and put it on the table. She seemed as normal as ever.
“Do you think that if I mentioned the man eating pie he would come back? Like if I was to say: ‘Look at the man sitting at the counter over there. He seems to be enjoying that pie of his.’” Her voice was cool.
“I suppose it might.”
He looked towards the far end of the diner. She turned and looked towards the counter to watch the man eating the pie.
“The author really has lost the plot, in more ways than one.” He drank from his coffee.
“Well I’m just glad that the man is back. What pie do you think he’s eating? Do you think we should ask?” Her eyes were fixed on the man at the counter.
“I mean, why not? It’s not as though anything more interesting is going to happen in this story. And if I had to guess what type of pie, I would say apple. What do you think…?”

Why are they so transfixed on the superfluous man and his unnecessary pie?!
Why don’t they do what I want them to?

They both slid out of the booth, leaving behind money for their coffees, and went over to the man at the counter.
“I think” Mary said, “it’ll be a cherry pie.”
Standing beside the man, she said to him: “Excuse me sir. You seem to be enjoying that pie greatly, and we just wanted to enquire as to what type it is.”
“It’s blueberry, and the best I’ve ever had,” he replied.
“Looks like we were both wrong.”
They thanked him for his answer and went outside. The air was cool but still. They walked down the street with no real sense of direction.

They can’t leave. This isn’t what’s supposed to happen!

“You know,” Mary began. “I don’t think your name has been mentioned this whole story.”
“It’s Jack O’Connor,” he said, answering the question that had been implied. “I think it wasn’t mentioned because the author couldn’t think of it.”
They stopped at the corner of the block.
“Well Jack, what’re we going to do now?”

Forget about this nonsense, go back to the diner and continue with the narrative as it’s supposed to be.

“What is there even to do at such an hour?” he asked, ignoring the author’s pleas. “We could go to the cinema. Are there any movies you want to go see?”
“There is one movie with Audrey Hepburn I want to watch, Charade. I’ve heard rather good things about it.”
“Very well, let’s go see that.”
They crossed the road and began in the direction of the East Village Cinema.

A man is dead and the culprit is still at large! Don’t they care to know who did it? Don’t they care to bring them to justice?

“We both know it was the brother who did it,” Jack said. “And he’s so riddled with guilt that he’ll turn himself in tomorrow. So there’s no need for us to do anything about it. It’ll resolve itself and anything we try will only waste our time.”
“So leave us alone would you,” Mary chimed in. “This is our story now! And quite frankly, it’s going a lot better now than when you were in charge of it.”

Is there anything lower than being slighted by your own characters?

“Probably. But there wouldn’t be much.”
They then turned and walked off into the night.