Disclaimer: Foyle's War was created by Anthony Horowitz, and the characters of Foyle, Elizabeth Addis, Sam and Adam Wainwright, Valentine et al., jointly created by Mr. Horowitz, Mr. Michael Kitchen, Ms. Hermione Gulliford, Ms. Honeysuckle Weeks and all the other brilliant actors. No infringement is intended.

Author's Notes: Many thanks to GiuliettaC for beta-reading and offering improvements to the manuscript.

Other Notes: Why this story?
At Christmas 2018 Anthony Horowitz published a Foyle's War story in the Mail on Sunday, set just after the Falklands War (1982) when Foyle was long retired. In the story he mentions Foyle's deceased second wife, Elizabeth.
Intrepid investigators 'at sarahthe1001' and 'at BritDetectives' questioned Mr. Horowitz on Twitter, "Which Elizabeth? Was it EA (E. Addis) or EL (E. Lewes, from S.2 episode Fifty Ships)?"
Horowitz replied on Dec. 23rd, "It was EA."
Fan reactions ranged from outrage to intrigued curiosity. How could Foyle possibly be reconciled with a woman who had betrayed him, and for whom he seemed to have contempt, as evidenced in the final scene of Elise.
On Tumblr the challenge was issued to FanFic writers (by blogger 'at thatvoice') to answer the call to duty.
This is my idea of how Foyle might forgive and come to admire (again) Dr. Elizabeth Addis.

Setting: The action follows immediately from the last scene in Elise.

Chapter 1

Continuing up the footpath away from the cemetery Foyle was dismayed to see the Deputy Director of the Security Service, Sir Alec Myerson, standing by a large black car, clearly waiting for him. Myerson had just delivered the brief eulogy over the grave of Hilda Pierce to a mere handful of mourners. Samantha Wainwright had just given him her final notice, and he had just turned away from a woman he had considered a potential friend, but who had betrayed his trust. He had decisions to make about his own immediate future and wished to leave this bleak scene behind him.

Reluctantly he walked over to Myerson,
"Oh. Thought we had the afternoon off."

"You do. Join me for a drink, Foyle."

It was more a command than an invitation. He cast a futile glance at the distant, retreating figure of Arthur Valentine. No help there. But Foyle's curiosity competed with his usual caution and his depressed frame of mind. Myerson had never included Foyle in end-of-day drinks in his office, nor made any overtures of a social nature. He doubted this conversation would be unrelated to work.

Foyle climbed into the back of the spacious saloon next to Myerson, and the driver shifted into gear and accelerated to no more than a sedate pace, befitting the solemn occasion they'd just attended.

"A bad business all around, this." Sir Alec summed up, watching out of the front window.
"Y-yes."
"I never cared for SOE," he continued — a refrain Foyle had heard before.
"Should have been under direct military command, with a simple chain of authority." Almost to himself he added,
"Skeletons will be falling out of closets for years. And not only figuratively."

Foyle noted it was the nearest Myerson had ever come to making a joke in his presence. Perhaps it wasn't a joke.
He gazed out the side window without comment, and Myerson went on,
"I'm very sorry to lose Miss Pierce. She was...highly effective. Had a deeply held sense of honour."
"Humph," Foyle grunted quietly.
"You'd take issue with that?"
"Well…"
"Miss Pierce had no particular appetite for spying on you, Foyle. It came from me. I ordered her to keep you under control, because of your infernal interference in the Strasser business."

Myerson paused and looked sideways at his passenger. More seemed required.
"Mrs. Addis is not a member of the Security Service. She was released from SOE on VE Day, went straight back to her college and has kept her head down ever since." Seeing the same sour expression on his passenger's face that he'd witnessed mere moments ago, Myerson continued,
"Have you not wondered what obligation Mrs. Addis was under to Miss Pierce? Why she might submit to such a request?"
Foyle glanced at the man,
"No."

At that moment they arrived at Myerson's club, where the Chief signed in his guest, and then led him to a pair of wingback chairs away from others in the room. After their drinks arrived, Sir Alec resumed the subject.
"What do you know of Mrs. Addis?"
"That she was two years at SOE Cairo Office, then transferred to the London Headquarters."
"Is that all you know? Did she tell you about it?"
Foyle only shook his head.
"No, of course not, she's still under the Official Secrets Act."
Myerson sipped his whisky thoughtfully, then stated,
"You crossed paths with a Lieutenant Colonel Wintringham in early '41, in your capacity as a policeman. Hill House."
"Yes," Foyle answered, puzzled at the change of subject.
"A complete idiot, yes?"
Foyle gave a curt nod.
"Well, I can tell you the staff at the Cairo Office would make Wintringham look like an administrative genius. Elizabeth Addis was thrown into that snake pit of jealousy and backstabbing and barely made it out alive. Others did not. She was, nominally, Planning Officer to Lord Glenconner, but since he really didn't care to be in Egypt, she was left to work with his No. 2, Brigadier Keble. An outright lunatic, by all reports."

Foyle shifted in his seat,
"Why are you telling me this?"

Myerson looked directly at him and took in a long breath.
"Because, Foyle," he replied gravely, "you're a man very preoccupied with justice, and there may be an opportunity here for you to bring justice to a past — and continuing — wrong, and to avoid committing an injustice yourself."

Foyle raised his eyebrows, somewhat affronted.

"Miss Pierce had promised to look into a matter deeply important to Mrs. Addis, and that is the only reason Mrs. Addis very reluctantly agreed to report your activities back to her."
Foyle was still sceptical. "A wrong for a wrong?"
Myerson tilted his head back and regarded Foyle down the length of his nose,
"Allow me to give you some reading matter, when we are next at the office."
"I have a book, thank-you." Foyle said offhandedly.

Myerson pursed his lips, and to Foyle's surprise, softened his imperious tone,
"Finish this last investigation for Miss Pierce, Foyle. It would've meant a lot to her."

To be continued...