The final mystery of Vienna Blood starts with a cold open of a young man in a military uniform, running through a forest. It's short-lived, as the series cuts back to the Liebermann household, who have gathered to celebrate patriarch Mendel's birthday. Max is there, sans Clara, raising eyebrows around the table. But his mother, Rachel, and sister, Leah, don't have much time to process when Max admits Clara has called the engagement off. Daniel (Luis Aue), Leah's son, is home from his boarding school, St Florian's, and his quiet presence suddenly bursts across the house as he takes a knife and slices his wrist open.
Amelia: There's an article in a journal; love is just a chemical.
When Leah takes her son upstairs, she discovers more. Daniel is covered with bruises like a gang beat him. The family is horrified, but they have a guess what may have happened. Daniel's father died a few years ago, and once Daniel was old enough, Leah sent him to St Florian's, a prestigious military academy, in hopes of him making the right connections in life. He's a sensitive, artistic, fatherless kid, and he's Jewish. The obvious answer is Daniel's probably being bullied, and the school is hiding it. With his family's blessing, Max asks Oskar to go with him to the school and open an inquiry.
Major Julius Reisinger (Johannes Krisch), the Headmaster, insists nothing is going on. But Daniel's calligraphy teacher and head of his House, Herr Lang (Rafael Gareisen), reveals the kid in the bed next to Daniel, Thomas Zelenka (Benjamin Posselt) died recently, drowned in the nearby lake just off school property. Under questioning, it turns out "recently" is all of ten days ago. It was declared an accident, even though no one properly investigated. That's because the officer in charge was von Bulow, an alumnus of the school. As for why parents weren't informed, this is a military academy. Exposure to death is an asset.
Hazing is also an asset, as far as the school is concerned. Evidence of it is everywhere, like the kid with a big burn mark on his palm who the science teacher, Bernhard Becker (Dominik Warta), is bandaging up. Becker sneers when Oskar mentions Max is a doctor of psychiatry, declaring Freud's method's nonsense. But this is Freudian stuff. As Max stares at the bed assignments, he realizes Daniel wasn't attempting suicide. He carved a "Zed", for Zelenka. As Reinhardt and Max leave, Reisinger tells Becker he'll pull strings at the police department to make sure they don't come back.
Upon returning to the office, Reinhardt learns Police Commissioner Strasser is going to be promoted. He and von Bulow will fight for the Commissioner's job. Though von Bulow bungled the Zelenka case, in Reinhardt's opinion, perhaps reopening it is not the smartest of political moves right now? But Oskar has other distractions. His wife, Elsa (Kristina Bangert), has come home. Unlike her husband, who mourns at their daughter's grave regularly, she's only beginning to process her grief. However, hopefully her return may mean a reconciliation.
Max is also getting a lecture on reconciliation, as Mendel attempts to convince his son to fight for Clara's heart. In what is possibly the best scene all season, Mendel talks about how love isn't a chemical reaction, but a choice. Oskar also thinks Max should go back to Clara, as they spend a calm evening playing billiards. Unfortunately, these words fall on deaf ears. Max is already running to Amelia to tell her he's no longer engaged, and he thinks he's in love with her. Max might be good at solving crimes but solving his life, not so much. Clara, recognizing she's dodging a bullet, makes it official and gives Max back his ring.
Daniel, meanwhile, is still catatonic. But at the mention of Zelenka, Daniel starts screaming, "I'm sorry," over and over. Max realizes his nephew knows something, when he finds an indecipherable code in Daniel's possessions. Perhaps he should be more worried his nephew has the same burn mark on his palm, the same one sported by his fellow cadets, meeting in the woods where Thomas died. They are frightened by Reinhardt, but their leader, Stefan Wolf (Stanislaus Steinbichler), lays down the cone of silence.
When Reinhardt and Max realize Zelenka's body also has the palm mark, they head back to the school. Lang admits the hazing at the school is atrocious. He tried to stop it when he first arrived, but these rituals are part of the fabric of the institution, passed from one generation to the next. (And it's still happening, as a new page of code and a cross of thrones appear on a new kid's pillow, summoning him.) Zelenka was the kind who would get it worse than most. His sister (Naemi Latzer) saying Thomas was gentle, eager to please, and an artist.
Armed with the knowledge Daniel went through this hazing, Max tries a new tactic: Inkblots! Daniel says he sees a wolf. Wolf, naturally, is the head bully, which Max remembers seeing on the bed-check list. Strasser says to tread carefully when Reinhardt asks for a warrant to interview the kids at the school, but concedes. Wolf pulls the old "Do you know who my father is," when confronted, as does every boy who follows until there's a laundry list of Vienna's most powerful men whose children Max and Oskar are questioning.
But it works. Staring at the boys in silence pulls confessions, from one boy's small-time "I stole a strudel," to Wolf admitting he bullies the boys who don't fit in. Finally, one kid snaps. There was a note Zelenka wrote, to "His Beloved." In it, he said he was running away to meet his love. They would go to his family and expose the terrible things happening at the school. Zelenka wasn't hazed to death, nor was this a suicide or accident. He was murdered to cover up the school's horrible practices.