Moritz and Hakim observe fifteen-year-old Azra selling suspicious bags at school. Homemade organic gummy bears, she explains, but Moritz doesn't believe a word of it. Azra threatens to hurt his little sister if he doesn't leave her alone. What's really in these gummy bears? When Moritz sneaks down to the attic at night to check the lab results, his mother secretly follows him. This leads to a shutdown of headquarters. The Peppercorns are devastated, but then the case takes an unexpected turn...

Jasina finds herself in the middle of a dramatic chase, during which she is secretly given a mini USB stick. The data stored on it leads the Peppercorns to the trail of an illegal wildlife trafficking ring. A bald eagle promptly disappears from the zoo—but unfortunately, so does Jasina, who was on the trail of the perpetrators... And all of this happens on the very day the Peppercorns have to say goodbye. Amy keeps her cool amidst all the excitement and passes the baton to two potential successors.

From the HQ window, Taara observes something in the building across the street that she considers suspicious. Jules is skeptical—the items the man over there has stashed away in the dead of night look like ordinary children's toys to him. Jules's opinion changes when Taara discovers that the rubber bouncy toy for toddlers is a recently stolen piece of modern art. What now? Still inexperienced in dealing with crime, the two set out to track down their first perpetrator—and find a new friend and cool co-detective in Malin.

There's a lot going on in Kofi's group home: Roommate Freddy is preparing to move out, a new roommate, Piet, is moving in, and then someone vandalizes the office, causing valuable items to disappear. Is troubleshooter Nico behind it? Or could supervisor Arne be right and Piet was just looking for attention? Taara, Jules, and Malin offer Kofi their help – and as the investigation progresses, Piet reveals himself not only to be innocent, but also to be a valuable detective and an excellent snoop.

In HafenCity, a homeless man is hit at night – with Alva's car. And the victim, whom Malin knows and likes as E.T., provides a description of the perpetrator that fits Alva perfectly. Since Malin's grandmother has a watertight alibi and the Pfefferkörners quickly realize that there's something fishy about E.T.'s statement as well, they begin to investigate. They discover that cars with a radio link are incredibly easy to steal. And that the homeless man who was hit had a good reason to lie. If they want to exonerate Alva, they have only one chance: They have to set a trap for the car thieves...

During a firefighting operation, Pascal suffers from dangerous smoke poisoning. Jules, who is already constantly worried about his father, wants to get to the bottom of the cause. Did someone neglect the maintenance of the breathing apparatus? Or is this possibly sabotage and a targeted attack on the fire department? Taara is skeptical and thinks Jules is just in panic mode again. Only Malin understands his fears and actively supports the investigation. A spontaneous declaration of love ensues – or is Jules on the wrong track here, too?

Kofi films his friend Till doing parkour, who immediately posts the video online and immediately garners likes and hearts from his fangirl Lea, who has been following him for a while. And not only that: Lea's father is a photographer and already has him in mind for an advertising campaign – test shots are scheduled for tomorrow! Kofi is happy for his friend, but shortly afterwards, Till's phone disappears. When it reappears, all the data has been deleted, including the address for the photo shoot. With Jules' help, the data is restored, and Till can leave for his appointment.

Kofi and Piet's group home has a new roommate, Milo Kaya. The sixteen-year-old is trying to escape from his criminal family clan with Arne's help. But he is suddenly suspected of stealing valuable professional tools: the stolen goods, including his fingerprints, are found in his trunk. Milo is so disappointed in him that he leaves the group home in a hurry. The Pfefferkörners, on the other hand, firmly believe in Arne's innocence and investigate on their own, visiting old friends and eventually visiting a children's play paradise.

Noah and Pfefferkorn Taara are the English losers in their class. Both suffer from the pressure to perform at school. When their teacher, Amsel, refuses to grant Noah time off for basketball training camp, he flies into a rage. Shortly thereafter, the teacher discovers that their car tires have been slashed. During interrogation, Noah confesses to the crime, but Taara doubts his guilt. His classmates Ella and Li Ming become the Pfefferkorns' targets. How far would the committed girls go for their environmental campaign "To School Without a Car"?

The radical animal rights organization TBF uncovers a doping scandal and suspects veterinarian Nina Berger of being partly responsible. The veterinarian is the mother of Piet's classmate Hanna and runs a practice where their dog Bagel is also vaccinated. When a stone flies through the practice window during treatment and a threatening letter from TBF appears, Piet begins to investigate. He discovers that Nina's daughter, Jule, is a staunch animal rights activist and that the two are at odds. But is she responsible for the attacks? Together, Piet and Hanna find new leads.

Early one morning while jogging, Pfefferkorn Malin hears a scream and spots an injured man who appears to have fallen off a building facade. But before she can make out his face, the figure flees, leaving Malin alone to face the police. It turns out that someone has been trying to steal copper pipes. Naturally, the Pfefferkorns want to solve the case, especially since Malin fears the perpetrator might be from her climbing club. However, when she is caught breaking into a locker, she is suspended from training – and feels misunderstood by everyone.

During a choir rehearsal at school, a fight breaks out between student Ana and her former best friend Janine – and Ana leaves the room crying. While trying to comfort her, Malin notices signs of abuse on Ana's arm. The Pfefferkörners try to mediate between the girls and learn a shocking revelation: Ana's father allegedly beat both Ana and Janine. But then it turns out that Janine lied to get revenge for filing a report with the youth welfare office. Before she can be confronted, Ana suddenly disappears without a trace.

On Girls&Boys Day at a bank, Malin, Kofi, Taara, and Jules become embroiled in a robbery and extortion case: Amelie, the bank director's daughter, is kidnapped and her mother is being blackmailed for four million euros in ransom. Thanks to Kofi's observations, the Peppercorns quickly learn who the criminals are, but all attempts to stop them in the bank fail. Kofi himself is in great danger. They must act quickly. At the same time, more than just friendship is developing between Kofi and Taara. The uncertain feelings and the danger demand all their courage.