'Van der Valk' Delivers a Cure for Cancer & an Open Ending for Season 4

It's been a hard road on Van der Valk this season trying to get Hendrik to go to a doctor and get an official medical test to confirm his cancer diagnosis and come up with a treatment plan. Fighting with a friend when you know they are being stubborn against their own best interest is a universal experience; fear drives people to do a lot of weird things. However! It is not a universal experience to get that friend blackout drunk and then use workplace (in this case, police) resources to give them medical tests against their will. Piet Van der Valk would probably be offended to be lumped in with that crowd, AND YET. His hijinx this week went beyond the pale, even for him. 

Piet decided to take matters into his own hands in the Season 4 finale episode by plying Hendrik with booze until he passed out and then wheeled him out to an ambulance where Julia and Lena were waiting. They started drawing blood when Hendrik officially woke up, rightfully freaked out, and ran off. Jules did at least admit that what they were doing was a crime and could cost them all their jobs, but shockingly, so many people went along with this ridiculous and violating plan*. 

(*No time to dwell on it or to make sure Hendrik didn't sue all of them because there was still a double homicide to solve. Is that an American worry?) 

It turns out that Freddie Klink used to employ the hitwoman who almost took out Lucienne last week as his bodyguard, making his connection to this case even more substantial. But Freddie also made a compelling argument that the glory of finding a potential cure for cancer would far outweigh the profit potential of sitting on it, and even Piet couldn't fight that logic. 

Continuing to trail Klink led the team directly to their hitwoman, Nettie, but they found her stabbed in the neck, and Klink was nowhere to be found. Hendrik discovered the murder weapon — lab scissors — and pointed out that Ruben Mesman's research clinic was only two streets away. The team went straight there and found Ruben holding Klink hostage, trying to force him to give up Tycho's potentially cancer-beating formula. 

Ruben discovered that his father, Ray (Romijn Conen), initially lied about the research. Klink wasn't trying to squash the research. He was funding it, and they were using the front of him as the bad guy to motivate Tycho to find the cure. When Ruben found out, he teamed up with Nettie to bring them all down, but she killed both Tycho and Ray before actually getting the formula. She was going to do the same to Klink for dumping her years prior, but Ruben killed her so that he could still potentially walk away with Tycho's formula and the patent. 

In Ruben's head, Tyhco had taken everything from him. He had the father-son relationship with Ray that Ruben coveted. He had Alis (Lia Macedo dos Santos), who Ruben had been lusting after for years. And Tycho made a world-changing discovery and would potentially end up with a Nobel Prize, while Ruben was still mistrusted because of his addiction problems. It feels like a few well-placed "I'm proud of yous" from Ray could have saved a lot of lives here, but hindsight is 20/20. 

Piet convinced Ruben that Klink didn't know the formula (which was true), and Ruben turned himself in without harming the billionaire. He went to prison, but the mystery of Tycho's cryptic formula still remained. The answer was in the emergency message he left for the police on the night of his death, which he signed "Ciao Bella." It was a clue referencing his and Alis' trip to Italy, which the team found a picture of earlier when forensics was studying Alis' apartment. Piet went back to Alis' place and checked the back of the photo from their vacation to find that Tycho had put the formula on the back of it. 

Hendrik was the most overjoyed to finally have an answer to the formula riddle, which led him to an important revelation. While he was still (again, RIGHTFULLY) pissed his friends had violated his wishes by having him tested against his will, it showed him how much they cared in a screwed-up way. That was motivation enough for him to go and get tested. The final scene of the episode showed the whole crew accompanying him to the doctor's office and watching him go inside to finally figure this out. 

We don't know the results of Hendrik's tests or what it'll mean for the team in the future. We also still have a lot of question about Piet's and Kalie's (Kim Riedle) relationship. They seem to be working together now, but there's still a lot of tension there. At the end of the case, Kalie told Lucienne that there was more to their breakup than Piet's dog dying. This means that we need to order Season 5 ASAP because we can't say goodbye to the show without knowing exactly what's wrong with Hendrik or what Kalie's big secret is. 

Van der Valk Seasons 1 through 4 are now available to stream in full on the PBS app, the PBS Masterpiece Prime Video Channel, and PBS Passport. Season 5 has not yet been confirmed.