This summary is in no way intended as a substitute for viewing this fabulous episode.
As Foyle and Sam pass the station reception desk, Sergeant Rivers reminds the DCS that he hasn't bought any tuppenny raffle tickets yet. Foyle is impressed when shown the large onion that will be the prize and he says he'll take a bob's worth.
Milner comes into the lobby and reports that he can't discover who is supplying Fenner with the goods. Foyle instructs him to let the man go, but notices that Milner looks glum and asks if he is all right. The sergeant attempts a smile and replies that he is.
Foyle goes to his office, leaving Sam at the desk. She asks Rivers if she may smell the onion because she hasn't seen one since Christmas. She takes a long, appreciative sniff, whereupon the sergeant announces, "That'll cost you a penny!"
As Jack Fenner locks up his hardware store that night, a car pulls up at the corner of the street and he sees two men drag from it a body-shaped load. Fenner is too busy concentrating on the action to hear someone approaching from behind and is knocked cold by a hefty bang on the head.
As Sam is leaving the station for home, she finds Milner still at his desk. She tells him that she has dropped the DCS at his home and is leaving the car at the station for the night. She smiles at Milner and asks if he wants to buy her a drink.
In the pub, Milner explains that his marriage is not working and Jane has gone back to Wales. He says that he is thinking of leaving Hastings. Sam's immediate response of "Oh, not you too" prompts Milner to query who else is leaving, and she mutters that it's nobody, and diverts his attention by asking why he wants to go. All he can say is that he's probably looking for a fresh start and when Sam remarks that Foyle will be very disappointed in him, he asks her not to mention it to him yet. Sam says that the two men need something to take their minds off things and a "jolly good murder" would do it. The two laugh.
During the night, a patrolling ARP warden is blown off his feet by a blast from an explosion in a nearby bookshop.
Foyle and Sam join Milner at the scene. In the building is a body of a young man, too badly disfigured to be identified. Milner explains that it looks as though the man had held a grenade to his head. The doors were locked, the key was in the deceased's pocket and the warden didn't see anyone else around, so it appears to be suicide. No identity card or ration book has been found, but the man had a solid gold pocket watch bearing the inscription: WRM - Congratulations - April 5th 1938.
In the street outside, Milner tells his boss that the shop has been closed for a while and points out that Fenner's place is directly opposite. Foyle instructs his sergeant to release some details of the watch inscription to the press, but for the time being, to describe the death as an accident.
A local watchmaker tells Milner that the watch is expensive and the marks on it indicate that it has been well used. It looks like an old watch but is a recent model, made after the date engraved on it.
In the station, Sam reads the newspaper report of the "accident" and comments to her boss that she thought it was suicide. He replies, "Perhaps."
Sam asks, "Won't you miss it, sir?"
"All this - police work."
The look on Foyle's face indicates that he doesn't want to discuss the subject, but before he can say so, the telephone rings. Sam continues. "I mean, if you join Naval Intelligence, it's all just paperwork."
Foyle picks up the phone and raises a forefinger to indicate firmly to his driver that she should stop talking. He responds to the message he has received by telling the caller that they are on their way. As he rises from his chair, Sam persists. "You see what I mean? Here we go again. You never know what's around the corner in this job."
Foyle gives a patient little smile, but says in staccato as he plonks his trilby onto his head, "That's enough. End of conversation. Subject's off limits. Thank you!" And he means it.
Foyle and Milner visit the Hastings home of a Mrs Thorndyke. On seeing the newspaper report she had told the police that she thought the dead man was her lodger, William Messinger. She is shown the watch and barely glancing at it, she identifies it as his. He had been with her for six months, but she doesn't know what he was doing in Hastings. She says his parents live in the town and when Foyle queries why, in that case, he would need the room, she says she doesn't know, but he was seeing a young lady called Marion Greenwood and perhaps he didn't want to take her home. In response to a question, Mrs Thorndyke tells Foyle that she has lived in the town with her husband for a long time, but Ernest died last year, aged only 63. Foyle asks if her husband was a Hastings' man and she says he was. When the DCS then asks what school her husband went to, she answers, "What do you want to know that for? What's that got to do with anything? I thought you wanted to know about Mr Messinger."
Foyle doesn't pursue the subject. Instead, he requests to see Messinger's room. In the room, the man's identity card and some money are found. A photograph of a young woman is on his bedside table. There is an envelope addressed to "Marion", containing a letter in which he says he can't live without her and that she will now know that he meant what he said. Foyle asks Mrs Thorndyke if it is Messinger's handwriting. She confirms that it is.
Back in the street, Milner remarks to his boss that he doesn't appear to think it was suicide. Foyle asks him his opinion and he says he doesn't think so, either.
In a large country house, Hilda complains to Wintringham that he went ahead with his plans against her advice. He is unrepentant, saying that she runs the section but he is director of operations. She tells him the plan is madness and cannot possibly work. He replies, "Why not? It's exactly the sort of operation we were put in place to achieve."
She tells him that there is already a problem and, indicating the newspaper article about the body being found, says he has been very unlucky because DCS Foyle is the investigating officer. She warns him that Foyle is not the provincial policeman he expected and won't leave this alone. "He may even find his way to you."
Wintringham is dismissive. Hilda warns him again, but he simply throws the newspaper into the wastebasket and snaps, "Forget him!"
In the police station, Milner tells Foyle that Fenner can't be found and Rivers informs him that Marion Greenwood is waiting to see him.
Marion says that someone gave the watch to Messinger for his birthday. She reads the letter and says it is not fair that he blames her for his suicide. She tells how they met when she was working in the bookshop. She doesn't know what his job was, only that it was very hush-hush and he was in London much of the time. She knows that his father, Sir Giles, is a major general, but she was never allowed near the family's mansion outside of Hastings. She and William used to meet in the bookshop, to which he had his own key, because it was the only place they could get privacy. Marion admits that she liked William but didn't love him. When she met someone else, she told him. He was very upset, but she didn't think he would do what he did. After the interview, Foyle explains to Milner that Sir Giles Messinger is "fairly big in Whitehall, economic warfare, something like that, but also rumoured to be associated with Military Intelligence."