‘Professor T’s Finale Exposes Secrets & Sticks the Emotional Landing

It’s the end of Professor T’s lively third season, and we finally get our payoff: the truth about Jasper’s father’s death. Throw in a murder mystery where the victim of a car crash died of suffocation, add the surprising death of a main character, and it’s quite the finale. Ben Miller gets to flex his acting chops as Jasper rides several emotional waves. He has been making personal strides all season, addressing the traumatic memories of his father’s suicide and its effect on his behavior and relationships – especially his OCD. He even goes ungloved by the end of the episode, which is reversed in a heartbreaking moment when Jasper re-dons his gloves after the aforementioned untimely death. 

Adelaide instructs the Dean to destroy a cache of her diaries and “that thing of Jasper’s.” Before the Dean can get there, Jasper meets Dr. Goldberg at Adelaide’s, and against her better judgment, Dr. G agrees to look in the attic. She locates Adelaide’s box of diaries. Jasper wants her to read them and report pertinent details, but she refuses. It’s up to him to betray his mother’s trust. He opts to put the diaries back, unread, and then notices a broken trophy in the box. Touching the trophy triggers a memory: his father’s feet swing in the air, and he can hear his father’s voice. Dr. G asks if it could have been someone else speaking. Upon closer inspection, the trophy is spattered with what may be blood. After returning the items to the attic and leaving, Jasper notices the Dean enter Adelaide’s house. The Dean later reports to Adelaide he burned her diaries and disposed of the trophy.

Jasper has been restored to his rightful place at Cambridge and begins a lecture on Narcissistic Personality Disorder to a roomful of students who burst into applause at his return. He calms them, then squirts sanitizer into his gloved hands, making them erupt into cheers once again. Jasper can’t help but smile. He gives us the theme of this week’s story: “The narcissistic parent will react with contempt, rage, psychological abuse, and physical violence when the objectified child unwittingly reneges on his obligation to act as the source of narcissistic supply.”

Before Donckers and Dan arrive on the scene of the fatal crash, we see teenager Seb Vermorel (Ben Wilson) watching from a hidden spot. The victim is Marianne Tierney (Anna Anning), the wife of Seb’s gymnastics coach, Peter (John Hollingworth), and co-owner of the gym where Seb trains. Peter is devastated when the police give him the news, which affects Dan tremendously. He comments on how short life is and grabs Donckers in a fierce hug.

Seb turns up at the police station with his parents, Leah (Flora Montgomery) and Duane (Gerald Kyd). With attempted coaching from his mother, Seb admits he was on the way to meet Marianne when he hit her car accidentally and didn’t realize it was her. He saw her get out of the vehicle and assumed she was okay, then fled the scene because he’d been drinking. When they learn Marianne was pregnant, and Peter infertile, the police deduce that she and Seb were having an affair. After learning of the pregnancy, Peter goes to the Vermorel home and attacks Seb and his car with a wrench. Dan and Donckers arrive just in time to subdue Peter. At the station, Peter goes even crazier when Donckers reveals Marianne was murdered – he runs his head into the wall until passing out. The police talk to the Vermorels again individually. Leah and Duane claim not to have known about the affair, while Seb scoffs at the implication. 

Too late, Jasper realizes the killer is the mother, not the father. Separately, Donckers gets Duane to confess the whole story to her. He admits Leah killed Marianne. Leah learned about the affair and followed Seb, stopping at the crash scene to smother Marianne while she was weak from her injuries. 

Uncharacteristically, Jasper abandons the police investigation without explanation, rushing to meet Dr. G, who tells him critical details she’s learned about his father’s death. She spoke with the coroner about his report and discovered he suspected foul play but was influenced by an eyewitness account from Wilfred Hamilton (the Dean). Jasper realizes the voice he heard was the Dean, not his father.

Jasper confronts Adelaide and the Dean at the hospital, accusing the Dean of killing his father and disguising it as suicide. Adelaide sets the record straight: she killed his father, not the Dean. Jasper’s father was very drunk and fought with her. Jasper tried to protect Adelaide from his father’s abuse, and in return, his father choked him. Adelaide hit her husband with the trophy to save Jasper, accidentally killing him. Jasper doesn’t remember the attack and is horrified that his mother let him believe the lie of suicide all these years. “My whole life, I’ve been blaming myself.” Adelaide attempts to explain her motivation was out of love, but Jasper counters that she’s a narcissist who only acted in her own interest.

Jasper has a meltdown that leads to a breakthrough: He calls Goswami to turn Adelaide in, compelled to tell the truth. But with Dr. G’s help, he hangs up instead, deciding not to implicate his mother for her crime. He forgives Adelaide, removing a glove to hold his mother’s bare hand. 

Jasper video-calls Donckers to tell her it’s Leah, not Duane, who killed Marianne. Donckers is already on the scene at the Vermorels’ house. Leah decides to flee, getting into her car though Donckers is in plain sight. Donckers is annoyed and stands in the car’s path to stop her – but Leah doesn’t stop.

Donckers smashes hard into Leah’s windshield and rolls to the ground. As Donckers lies immobile, Leah works up her nerves and slams on the gas, running Donckers over a second time. Jasper calls an ambulance and arrives to find Donckers barely alive. She’s crying and says she’s cold. Jasper puts his coat over her as Dan and the EMTs appear. Dan had just successfully proposed to Donckers in this episode, and he is absolutely shattered. 

• We assume Donckers is dead because of the tone of the final scene (an aerial shot getting further and further away) and the lack of music over the end credits. Her pending transfer to a new precinct foreshadowed the end of her character, but her death was unexpected and tragic. 
• Jasper repaired his relationship with Adelaide, but the new trauma of feeling responsible for Donckers’ death will haunt him. 
• Season 4 is already greenlit.

All episodes of Professor T Seasons 1 through 3 are available to stream on the PBS app, the PBS Masterpiece Prime Video Channel, and PBS Passport. Season 4 is expected out in 2025.