Ludwig episode 5 sees John "Ludwig" Taylor (David Mitchell) investigate the murder of a headmaster at a posh school, while Lucy Betts-Taylor (Anna Maxwell Martin) does some sleuthing of her own.
The episode opens at a grand-looking school. Someone knocks at the headmaster’s office and a bell tolls… . After the weekend, teacher Freya Chordwell (ex-EastEnders star Rose Ayling-Ellis) tries to get into the headmaster's office but it is locked. Once inside, she sees the headmaster's dead body.
Lucy and Henry tell John that someone has hacked James's phone. It means that the phone can see withheld numbers, including the call he took the previous night from — we think — DI Matt Neville (Karl Pilkington). Did Holly hack the phone? Has she been helping James? Lucy says she thinks it must be DI Matt Neville. Lucy tells John he needs to talk to Holly alone…
John tries to grab Holly in the lift but Russell says it's time to go back to school. Simon says the headmaster took his own life and says there's even a note. John observes a string of errors in the note, would a former head of English make those? John and Russell are for once in agreement: the crime scene has been staged and it’s a murder.
We seem to have a Death in Paradise-style locked room puzzle for John to crack.
Henry has some dark web skills and tracks down where DI Matt Neville lives. He's in a house in Wales and it's registered in the name of Gillian Botley, Lucy seems to know of her.
John and Russell interview Freya. She says she's engaged to Mr Bishop (Sam Swainsbury), the PE teacher, who was away over the weekend. Asked if she saw anyone around the time of the murder, she says she saw one of the housemasters, Mr Todd (Sir Derek Jacobi), who John says he knows.
Locked room puzzle
They go to question John's old teacher Mr Todd, who seems vague and forgetful. He does though recall the headmaster having a heated exchange with Mr Bishop. He says Mr Bishop is a bully.
John is disturbed by Mr Todd's apparent mental decline. We see a flashback to Mr Todd rescuing young John from a couple of school bullies.
They speak to Mr Bishop and John is a bit shocked to discover he proposed to Freya from Scotland by video call. He reveals that the headmaster was on the verge of sacking Mr Todd — possible motive? The argument he had turned out to be whether or not to take action against a bright ruby prospect smoking dope. John doesn't like the PE teacher.
They discuss the suspects: ambitious Freya, a dope-smoking rugby boy, Isaac, the angry sports master, and soon-to-be-fired Mr Todd. John is frustrated by the lock problem.
Lucy claims to be heading to Leeds to photograph a wedding and tells John and Henry they can have a lad's night! "What does that entail?" asks a worried John.
The next day Simon tells John the post mortem says the victim was strangled. John is alarmed that DCS Carol Shaw (Dorothy Atkinson) is with Holly and wants to see him. But Shaw just wants him to crack the case and Holly has been looking at the headmaster's computer. She's discovered two letters one about Issac's dope smoking and the other about accusations of inappropriate behavior with a student by Mr Bishop.
John doesn't like PE teachers and he might be right with Mr Bishop, who's blatantly inappropriate with a female pupil during a rugby match.
They interview Mr Bishop who gets angry when John says he saw him act inappropriately. He claims to have just patted the girl on the back. He's certainly an arrogant unpleasant man but is he the killer?
Meanwhile, Lucy is driving to Wales. And Herny has hidden in the car. Lucy admits to knowing who Botley is. He says it was Matt's wife's maiden name.
Freya reveals that the argument she had with Mr Bishop was over her spotting Isaac with the joint. He thought she shouldn't report it, but she did. She explains how they parted on bad terms but then he proposed in a video message.
John is still trying to work out what happened with the door. We flashback again to young John and see Mr Todd being kind to him. He sets young Ludwig a puzzle and tells him also how to set them. You can see the boy's hooked.
Back in the present, John goes to visit Mr Todd. John asks how did the killer leave through a locked door. But Mr Todd replies the one thing they do know is the killer can't have left the room because that's impossible. Upon leaving he bumps into the bullying Mr Bishop and they have a brief war of words.
John returns to Lucy's empty house. Lucy phones and John spills his heart out, saying he's worried he'll end up like his mentor Mr Todd, old, lonely, and losing his mind. John looks at a banana peel and something seems to twig in his mind.
Holly gives John dramatic news about his brother
John returns late to the office and runs into Holly, but they don't know Simon is also there, listening. He asks her why she covered him over the log-ins. And she starts going on about how he kissed her at the office Christmas party! It seems his brother cheated on Lucy. Holly storms off and John looks shocked. Looking at the case photos he seems to have solved it…
The next day, Lucy gives Henry the slip. Back at the school, John gathers the suspects. John tells them that the killer never left the office. John says Mr Bishop camped out for three days in the office next to the corpse of the headmaster.
We flashback to the caretaker opening the door and see Mr Bishop hiding behind it. In the confusion, Mr Bishop slipped out of the room as Freya told the children to get out of the area. John explains how he'd thrown out a banana peel last night and two hours later it was already browning, yet the apple core he saw in the headmaster's bin had barely turned its shade. "It could only have been eaten that morning inside the locked room," he concludes.
But Mr Bishop laughs off the apple and claims he ate it in a meeting before the weekend. John says he has more evidence and that Freya was crucial to his plan. He thought with Freya in charge of the school she'd dismiss the accusations of inappropriate behavior against him. However, he knew he had to stay with her and was worried by the argument they'd had so that's why he made the strange marriage proposal via video.
In the background of the video call, you can hear the distinctive school bells, illustrating that Mr Bishop was at the school and not in Scotland where he claimed to be. Mr Bishop rushes at John but is neatly tripped up by Mr Todd and arrested for murder.
We meet DI Matt Neville
Lucy knocks on a door in Wales and DI Matt Neville answers! Matt's wife is terrified and asks Lucy to leave. He says sorry and shuts the door on her.
John goes to thank Mr Todd, but Mr Todd comes out with a bombshell question: why is he pretending to be his brother? John promises it's for a noble reason and Mr Todd wishes him well.
Lucy picks up Henry and they head home. Back at the office, Simon seems to be upset by what he discovered about his boss.
John and Lucy lie to each other that they have nothing to report. In the middle of the night, Lucy gets a call from Holly. She says she needs to speak to her now about James! And Lucy heads off...
