Ludwig episode 4 sees John "Ludwig" Taylor (David Mitchell) investigate a murder at a building site, while he starts to get suspicious about Holly Pinder (Sophie Willan). Here's everything that happened in the fourth episode (spoilers ahead)...
We open at a building site and one of the builders falls to his death. Was he pushed?
Lucy thumps John awake with a newspaper and says his latest detetective escapades have made page 5. John's rather taken that they're calling him "Supercop!".
"Do me a favor John, don't solve any murders today," pleads Lucy, who tells him to get on with cracking his brother's notebook.
Next, we see John and Russell at the building site. DI Russell Carter (Dipo Ola) reckons it's a workplace accident.
DC Simon Evans (Gerran Howell) informs them that there were five builders present at the time of the death. John, wearing a fetching safety hat, has to climb a ladder to get to where the man fell from.
John is then disturbed by a warning of death sign, but the builder says not to worry and he's not sure why it's there (might this be crucial?). The victim was called Martin and Russell thinks it looks like an accident. But there's another safety sign that wasn't meant to be there. John spots some water, what's that about?
Everyone hates the victim
John looks at the security footage and declares one of the builders is a murderer! It shows that the security signs weren't there in the morning and John says no one will admit putting them up. He also thinks the electrical generator has been tampered with. It was murder, he pleads to the unimpressed-looking DCS Carol Shaw (Dorothy Atkinson).
John tells Lucy how the "computer woman", Holly, almost caught him earlier looking at the Sinclair crime report. Luckily she thought he was just looking at dodgy material online! Lucy laughs at this news.
Back at the building site, the boss man, Connor, gets angry when John arrives to question everyone. First, they talk to Gary and Zara. She describes the victim as an "a***hole", which seems a bit mean as he's just died. She went out on a date with him. She also reveals that "joker" Martin convinced Polish builder Stefan he was going to be deported. Actually, he does sound like an "a***hole".
They next question Stefan and Ojay. It's revealed Martin said sorry to Stefan about his immigration gag at the end of yesterday's shift.
John spots a water dispenser discared in the skip. He reckons the water was poured onto the generator and then thrown away in the skip. He rescues the generator from being taken away and puts the wires back in it as he recalls them being.
He asks Connor, who's a trained electrician, what would happen if someone pressed the button, which was wet when the wires were in the wrong sockets. He replies they would get an electric shock, but it wouldn’t kill them. But John replies enough to knock them from their feet through a safety rail that's been deliberately loosened.
John notices one of his Ludwig puzzle books at the building site and is impressed to see all the puzzles done.
Holly says the victim was a catfish, someone who pretends they're someone they’re not, and appears to give John a knowing look.
Alice points out that John's theory relies on the killer not only knowing the movements of the victim but also everyone else on the site to ensure the victim walked into the trap set and not a different builder. How? John says it's possible but they'd have to be a genius.
Back at Lucy's, she's developing some photos. Henry walks in and they argue over his father. John's disturbed by the building site case and thinks the killer is taunting him.
Find out what reverse chess is!
John goes to Henry’s room and tells him his mother is crying downstairs. Henry goes down to comfort her and they make up.
Meanwhile, John studies the chess game Henry and his dad were playing before he vanished. He glances at the puzzle book he took from the building site and a reverse chess game he set, which he notes is completed. He'd told Henry reverse chess, is where you use logic to work out the previous move rather than the next move, never caught on as it was too hard. But not too hard for whoever owned the puzzle book. Can he reverse the "pieces" on the building site to work out what happened?
John gathers the builders together and explains how the "genius" murderer predicted everyone’s movements.
DC Simon Evans (Gerran Howell) brings out a chess set for John to demonstrate on, but, much to the amusement of everyone else, it turns out to be a children's set.
John then explains all the moves by the killer to ensure the victim walked into the death trap, was electrocuted, and fell to his death. John says Zara made the first move in the killer's game but she wasn't the killer. She was manipulated. And John turns to Gary and declares him the mastermind.
As to motive, John says that prankster Martin invented Gary's girlfriend online and a mixture of pride and arrogance led him to kill. Gary knocks back John's DNA evidence he touched the water bottle and says "your move'. John then takes them all outside and proves beyond doubt that the water bottle must have gone down the shoot, thus proving Gary was on the floor where the victim fell. Gary congratulates John and John returns to Gary his puzzle book, which he has signed as Ludwig! Gary is arrested.
Later in the car park, Holly tells John the Chief Constable has been accessing a lot of files from his computer `— we know John is using that login. She tells him she's wiped the system for him, but she won't do it again.
Back at the house, Lucy asks if John wants to watch a film but he says he wants to crack on with finding James.
John picks up the phone and the caller asks what he's playing at. "Why are you back there? What the hell are you doing? James?" The caller hangs up. John doesn’t know who it is but we'd guess it's DI Matt Neville (Karl Pilkington), James's cop partner.
Meanwhile, we see the silhouette of what might be Holly looking at a computer with a covert photo of John on it. Not only that there's a whole board of photos of John and James, clearly showing she knows John isn't James.
