Episode 4 of "Blind Sherlock" unfolds with the German police eager to apprehend the motorcycle assassins. However, Suus declines, as they require the bikers to reach either Lennon or McCartney. Roman is left with six hours to uncover McCartney's identity, endlessly looping through the golf club audios.
With five hours remaining, the bikers make a pitstop at a gas station. Tess and Saafi arrive, secretly planting a bug on one of the bikes. It's a tense standoff as the bikers almost spot Tess, but she manages to escape with a convincing sob story.
Roman continues to delve into the audio, recognizing a memory from his past. A flashback reveals him and his father playing at a car wash. The mood darkens when they receive news that his mother's cancer has returned. Currently, Roman narrows McCartney's location to a car wash with an automated tunnel.
The stakes rise as the bikers inadvertently reveal they possess 4.5 pounds of explosives. Suus demands their immediate arrest, considering the massive collateral damage if they bomb the Hook. Unfortunately, Mayor Limon refuses, ordering them to focus on capturing McCartney or Lennon. Frustrated, Suus lashes out at Roman, who storms off in a rage.
Meryem sits with him by the river, triggering a memory that helps identify another sound from the audio. In a flashback, young Meryem and Roman yearn for a boat ride but are not allowed. They sneak out one day, only for Meryem to fall off the boat. Roman is helpless until someone else saves Meryem. Enraged, Meryem's father takes her away from the institute, passing a fire truck as they leave.
In the present, Roman realizes that McCartney's car wash is near a fire station due to the constant sirens. Unfortunately, that barely narrows it down.
Finally, another memory surfaces. It's the first time Roman and Caro met. It had been raining, and they ended up bonding and dancing on the street. Rain had been falling on powerlines. Currently, he hears rain hitting the powerline above the car wash. There's only one that fits the criteria - Kings Car Wash. They only have an hour left, and the cops race over to the car wash. However, it turns out to be the wrong one.
Suus is furious with Roman for messing up and orders the cops to stop the bikers. They set up a fake sobriety checkpoint. But the bikers get jumpy and try to make a run for it. One trips, while the other crashes into a van and dies as the explosives detonate. Roman is shocked by the aftermath and ignores all calls until his brother shows up with bad news. Caro has been infected while working at the clinic, but the baby is safe. The case is wrapped up. Mayor Limon pins all the murders on the bikers and orders the task force to move on to new cases, like that of a runaway teen. Roman is frustrated and goes as far as to tell the Graauw's that the real culprit is still free.
The mood is lightened when Tess announces a farewell party for Meryem. Roman is disappointed as they don't need an Uzbek translator anymore. However, the team ends up having fun, drinking and dancing. But as a drunk Roman makes his way home, he thinks of Yaqub being a good father, him dropping his nephew, and the car wash fiasco. He forgets to pick up Caro from the hospital, and she is upset. He ends up ranting to her how he will be a burden to his child. Caro tries to comfort him but is shocked when he confesses that for a heartbeat, he had hoped their unborn child would die from the infection.
His bad mood continues the next day when the task force tries to lock him out of accessing the McCartney tapes. He makes a scene and is suspended. He goes home and sees that Caro isn't there.
