Petri's colleague is arrested, and Petri and his wife make amends. It's time for Julius, the young runaway, to say goodbye to Harry and go home – but Dirk has one last surprise.

Autumn in the Alps brings with it all kinds of new sights: the woolly sheep are rounded up by their owners, the larches are ablaze in color, the squirrels prepare for winter, and the mating battles are in full force among the stags.

As autumn approaches, the sheep are brought back to their winter quarters. In this segment, we also see how beautiful the region is in the evenings.

While Dirk bonds with the young runaway, Katja figures out what actually happened at the Harms company.

Konstantin, the new temp worker at the pet store, wonders why he's even needed considering how little money the store is making. Meanwhile, owner Johannes uses the store's problems to try to bring his ex-wife Marion – who also happens to be his neighbor – back into his life.

Canyoning is another popular activity in the Alps, but it isn't for the faint of heart. In a glorious natural setting, the group faces some tough passages and harrowing jumps over waterfalls.

Katja and Dirk arrive in time to stop Mr. Petri's madness and bring him in to the station. Meanwhile, Lothar finds out the truth about their supervisor.

Germany is not a big enough country to devote all of its land to creating renewable energy – but there is another place with vast expanses of empty space and limitless sunshine.

Whitewater rafting and kayaking are very popular but also very dangerous sports in the Alps. Here we see some remarkable footage of a few daring individuals making their way through the thundering rapids.

Henning finds a potential lead regarding the runaway boy's identity, while Petri turns up at his former workplace yet again – this time armed.

In this segment, we finally glimpse the peak of the Großvenediger. Back down in the valley, families make hay without the usual farm machinery.

Henning shows up at Harry's to discuss the problems he's experiencing in his relationship, and is disappointed when Harry expresses the same opinions as his girlfriend. Then the doorbell rings...

In this segment, we visit quaint settlements, a chapel carved into a rock, and a waterfall that seems to disappear into the earth, all at the foot of some of the tallest mountains in Europe.

Walter Petri refuses to believe that one of his designs could have been flawed, and is furious at his wife for talking with the company's boss behind his back.

In this video, physicist and author Harald Lesch talks about how Germany could phase out coal and nuclear power completely and still meet all of its energy needs.