Sam is called in to a stabbing at a mill. To his surprise, the mill turns out to be a building which in the future would be turned into a block of flats, one of them his.
The victim is Saunders, a loom operator, who had a history of defying the mill workers’ union. Gene states that cases like this always follow a pattern –the first person to speak is the culprit.
They address a crowd of millers, and the first one to speak is Ted Bannister, who Gene immediately pegs as being guilty. Sam disagrees, claiming that Ted was unfit and much older than Saunders, meaning that it’s highly unlikely that he would have attacked Saunders without him fighting back.
Gene decides to turn their disagreement into a bet, with the stakes ten pounds and a Party Seven. After employing state-of-the-art research technology (i.e. Google), I was able to discover that a Party Seven appears to have been a tin of beer that was popular in the late 60s and early 70s.
Sam is reluctant at first, but after pressure from the other detectives, accepts the bet. He immediately enlists Annie and Chris to help him.
Interviews with the millers reveal that Ted got into a fight with Saunders in a pub the previous evening. A witness also puts Ted at leaving the mill at 2:30 in the morning.
Along with that, Sam finds a footprint at the crime that matches Ted’s. Ted is arrested, and the chances of Sam winning the bet don’t look good. But we all know that Sam is going to win the bet eventually.
In the meantime, Gene gives Sam another case to work on at the same time, this one involving Dodds, a fence who was arrested for possession of illegal firearms. As it’s unusual for more than one case to feature in an episode, the two are bound to be connected in some way.
Sam interviews Ted, who denies killing Saunders until Gene arrives with a bloodstained shirt found in Ted’s garden shed. This, combined with Gene’s statement that the mill will stay closed until the enquiry is over (meaning that the workers don’t get paid), is enough for Ted to do an about turn and confess.
Gene is ready to claim victory, but Sam is unhappy with the content of Ted’s confession. He states that the bet still stands, and sends the shirt to forensics in order to compare the blood with that of the victim’s.
Meanwhile, Sam tackles the Dodds case. He, Chris and Ray stake out the place where Dodds is to drop off the guns. It’s an outside toilet, and unfortunately for them, someone is able to climb through the back window and make off the guns without them noticing.
More bad news ensues when the blood on the shirt found in Ted’s shed comes back as a match for Saunders’. Things go from bad to worse when that night Sam gets another visit from the test card girl.
In the morning Sam receives the forensics report on Saunders, which reveals that he was killed at nine o’clock. As Ted was still in the pub at that time, he couldn’t have been the killer.
Sam and Gene return to the mill and examine the loom Saunders had been working on. Sam notices that the belt on the loom is a new one that hasn’t been used.
He realises that the belt must have snapped and, being at high tension, would have hit Saunders with enough force to cause the wounds. So in other words, it was an accident rather than a murder.
Sam and Gene talk to Ted again, who says that he went to the mill in order to confront Saunders, but found him there dead. He fitted a new belt and tried to clean things up so that the accident wouldn’t result in the mill being closed down.
Later on, Sam is going through the tapes he made of the interviews with the mill employees, and comes across one of Tina, the girlfriend of Ted’s son Derek. Tina says something about going through the back and picking up the bag.
Sam suspects that Tina is referring to the guns which they lost earlier in the episode. When questioned, Tina confirms this and tells them that Derek was planning to steal the wages from the mill. So the two cases were connected after all.
The detectives arm themselves and head to the mill. They ambush the would-be thieves, and manage to stop three of them, while the fourth (we don’t see him, but it’s guaranteed to be Derek) runs off, followed by Sam.
Sam finds Derek, but Derek forces him to drop his gun. Gene then arrives, and also puts his gun down when Derek threatens to shoot Sam.
The two of them try to convince Derek to surrender, and while Derek is distracted by Gene, Sam goes for his gun. Derek fires at Sam, but misses, by which time Gene has regained his gun and shot Derek in the shoulder. Sam experiences the show’s equivalent of seeing his life flash before his eyes, which in this case consists of the images from the woods we’ve seen in previous episodes, but with the test card girl thrown in as well for good measure.
Back at the pub, the detectives prepare to celebrate their success. Gene brings in the Party Seven, and together he and Sam open it.
Or at least, prepare to open it. To open a Party Seven requires two people to prise the lid off with screwdrivers and hammers, and the episode closes with the two of them positioning the screwdrivers and raising the hammers.