After a night shift policewoman Nina takes the metro home. Two hooded guys beat her up; phone and police gun are stolen. Nina, suffering from PTSD, is sure there was third man not caught by security camera. What is this trio up to?

It's a strange conference this morning in PK 14: Lukas steals Jessy's letter with the news that she has passed the aptitude test for the mobile task force. Questioning faces: Does Jessy want to leave? Ms. Küppers, known for her unparalleled discipline, also seems downright nervous this morning and irritates the team with a saying about the passage of time. When Daniel also gives Harry and Piet tips for observing car thieves, it seems high time to end the meeting. Hannes' trained antennas pick up the signals: Jessy is in love with Piet. The team is puzzled by Ms. Küppers' spontaneous departure for vacation. No one suspects that the boss has to deal with a cancer diagnosis.

The officers from PK 14 are still undecided as to what is worse: that Ms. Küppers has taken an indefinite leave of absence or that Daniel is heading the police station for the time being. Ms. Küppers, confronted with a breast cancer diagnosis, is desperately trying to make a bucket list. But she can't think of anything she really wants to do in view of the premature end of her life. She is more concerned with the question of why the oncologist Dr. Wagner was attacked and beaten in her practice without the perpetrator stealing anything. When it turns out that another patient was wrongly diagnosed with cancer, the officers from PK 14 are investigating at full speed. Meanwhile, it is becoming increasingly clear to Jessy that she cannot possibly continue working here.

The upcoming Valentine's Day brings a whole range of feelings to PK 14 - both good and bad. Oliver Hahne's love for Jeanette Preuss is obsessive and pathological, the stalker is not allowed to come closer than 200 meters to his victim. But even this court order does not stop the man from continuing to stalk Jeanette Preuss. Worse still: he begins to destroy the desperate woman's life bit by bit. Nina Sieveking and Lukas Petersen's hands are tied, however, as long as they do not catch Hahne in the act. Hannes Krabbe wants to express his admiration for Mrs. Küppers on Valentine's Day, but this can only be done indirectly. That is why he initiates a "Valentine's Secret Santa". The only problem is that the piece of paper with Küppers' name on it just won't end up with him, despite attempts to swap it. For Piet Wellbrook, Secret Santa is exactly what he doesn't need right now. Together with Harry Möller, he is looking for a polite thief who leaves notes in shops stating when he will pay for the stolen goods. Behind this lies a touching love story that even awakens a romantic streak in Piet.

Shortly for planned beginning of the concert main artist Mick walks away. His wife and manager Loki is desperate. Mick has a head wound. Falsified tickets are sold. Küppers loses a class photo.

Sebastian takes the fire arm away that doorman Andree possesses illegally. The police discovers that prepper Sebastian withholds his two sons a normal life. Mother died because of COVID-19. Hannes' emergency stock has a short expiry date.

Richard and 'Snake' committed a bank robbery. The loot has never been found. Now Richard gets out of prison and claims his old phone. Piet misses his two daughters. Nina and Lukas fetch a snake dumped by Sigi. Hannes worries about Küppers.

Jew Selma calls the police when neo-Nazis terrorize the neighborhood. Hannes gets a visit from his nephew Benni (ex-Nazi) and his pregnant life partner Marisa who is the ex of Nazi-leader Patrick. Will Hannes and Piet leave the team?

Burglar Jacky is arrested and brought to the station. Someone says that he carries a potentially dangerous virus with him. Helmut applies for the vacant PK14-job. Harry has to cope with cheeky Nils.

Deacon Fiete tries to give Vietnamese Cuong a better life. Elias seems to hunt Cuong because of cocaine theft. Someone sabotages Dora's hug meetings. Torsten fears that he is under the curse of an African carved skull.

Beim Ehepaar Stöver laufen die typischen Schemata häuslicher Gewalt ab: Egon Stöver misshandelt seine Frau Vivian, die sich dennoch nicht von ihm lösen kann und seinen entschuldigenden Beteuerungen immer wieder Glauben schenkt.Lukas Petersen und Daniel Schirmer durchschauen die Spirale der Gewalt und verzweifeln fast an ihrer Machtlosigkeit. Doch dann greift Vivians Schwester Barbara zu einem äußerst gewagten Mittel, um Vivian endlich dazu zu bewegen, ihren Mann anzuzeigen.Sehr persönlich wird es gleichzeitig auch für Frau Küppers. Sie stellt sich der Konfrontation mit den Kindern ihrer verstorbenen besten Freundin und gesteht ein, dass sie Tobias und Sina nach dem Tod ihrer Mutter im Stich gelassen hat. Als sich herausstellt, dass Sina kriminelle Energie entwickelt, um ihrem Bruder zu helfen, ist das die Chance für die Kommissariatsleiterin, vieles wiedergutzumachen.

Dass Daniel Schirmer ein kluger Kopf ist, wissen die Kollegen vom PK 14 längst. Und dann tritt er den Beweis sogar öffentlich an: als Kandidat in der Sendung "Das Vorabend Quiz" mit Moderator Yared Dibaba. Und tatsächlich: Daniel gewinnt 3000 Euro. Allerdings stellt sich heraus, dass das bar ausgehändigte Preisgeld gefälscht ist. Nina Sieveking und Lukas Petersen nehmen die Fährte auf dem Studiogelände auf und versuchen, dem Betrug zwischen Cateringwagen, Requisite und Fernsehproduktionshallen auf die Spur zu kommen.Während Quizfragen rund um das Thema Falschgeld auf der Wache - und speziell zwischen Daniel und seinem neuen Kollegen Helmut Husmann - zum Running Gag werden und die Kaffeekasse schnell aufstocken, forschen Harry Möller und Nils Sanchez nach der Absenderin ominöser Liebesbriefe aus der Dominikanischen Republik. Astrid Rath erhält sie von ihrer Exfreundin, die allerdings bereits vor zwei Jahren verstorben ist.