A stranger asks Thorsten Falke to meet him. He hopes, he says, that the commissioner will keep a promise that is more than 20 years old and help him out of an emergency. Since the stranger demands a commitment without revealing the further circumstances, Falke refuses. Shortly afterwards the man is pulled dead from the Elbe. It turns out he had been living under a false identity. In order to find out who the man really was, Falke and his colleague Julia Grosz have to delve deep into their own past. And with the man the two ultimately suspect, nothing seems to be as initially assumed.

Sheldon makes friends with an upperclassmen learning a new field of science. Meanwhile, George Sr. and Mary have a disagreement on Sheldon's new social life.

After Sheldon loses the competition in the science fair he loses his edge and passion for science and finds his new comfort zone in acting.

Sheldon is being followed around by a bully and must find a way to use self defense to fight back

Mary bans Sheldon from reading a mature comic book, and Sheldon decides it's time to stop living under Mary's thumb.

When Sheldon is no longer academically challenged at Medford High, he audits a college class taught by Dr. John Sturgis.

A battle erupts between the Coopers and Sparks when the Sparkses' new dog terrorizes Sheldon.

While Sheldon is busy obsessing over the status of Meemaw's budding relationship with his mentor, Dr. Sturgis, George and Mary attempt to bond with their other kids.

When Meemaw is pursued by two gentlemen callers, Sheldon interferes, forcing her to set some ground rules.

Sheldon dismantles the refrigerator to stop an annoying hum, then gets a paper route to pay for the repairs.

At Lübeck's old town market, a man disarms a patrol officer and takes a young passer-by hostage. Inspectors Finn Kiesewetter and Lars Englen pursue the perpetrator into a parking garage. When Lars comes into the perpetrator's line of fire, Finn has to decide in a split second: he shoots and fatally hits the hostage taker. Shocked and deeply shaken, Finn has to undergo the usual examinations. When the hostage unexpectedly states during interrogation that the man had already surrendered before the shot was fired, Finn is suspended from duty and branded the shooter by the press. Linda Stamm from Internal Investigations resolutely starts the investigation, Finn is threatened with charges. Emotionally affected, he retreats to the old holiday home on the Baltic Sea. While his old friend Elke Rasmussen wants to support him there, Lars Englen and his colleague Gregor Michalski try to prove Finn's innocence. Why has the situation at the old town market escalated so much? When the two investigators begin to understand the background, it is already too late. Finn and Elke Rasmussen find themselves in mortal danger.

Twelve-year-old orphan Paula accidentally witnesses a shootout in which a woman is killed. Because she was seen, Paula has to fear for her life. But the girl doesn't dare to go to the police because the two perpetrators have disguised themselves as police officers. When the woman's body is found on the Schwanitz coastline, she has nothing with her except a note with the words "Goblin Number Four". A big mystery for Hauke Jacobs and Hannah Wagner, which doesn't get any less unusual. The woman's name and origin cannot be determined and apparently no one misses her.

After a life-threatening police operation, Hubert and Girwidz try to get other thoughts on a common mountain tour. At the border stone 147 they come across two corpses, one on the German and the other on the Austrian side.

Meemaw intervenes when Sheldon gets jealous of Dr. Sturgis bonding with Paige, another 10-year-old genius. In the meantime, Mary invites Paige's family over for a play date.

Sheldon becomes an unlikely ally when a tragedy in the community shakes Mary's faith.

When Sheldon's father asks him to keep a secret from Mary, the stress of not being honest drives him at Tam's for his first sleepover.

Dr. Sturgis recommends Sheldon and Missy for a university research study on twins, and Mary is unhappy when the test results go to Sheldon's head.

Mary clashes with Sheldon's drama teacher over plans for a Halloween fundraiser for the church. Also, Georgie falls for a rebellious teenage girl that Sheldon is tutoring.

Sheldon gets into trouble with fellow child genius Paige at the science museum; George Sr. is forced to play therapist to Paige's bickering parents; and Mary, Georgie, and Missy help Meemaw with a garage sale.

A video game takes over Sheldon and Meemaw's life; George Sr. is jealous when Georgie bonds with Herschel at the auto shop.

Sheldon studies his family for a psychology project; a Thanksgiving dinner turns into a family fight when Georgie Sr. is offered a job Oklahoma.