Sisters Mona and Marie now run the "Sonnengruß" guesthouse on the North Sea together. But the hotel business is anything but harmonious.

Mona (Maren Kroymann) misses her old life in Düsseldorf's high society, and Marie (Ulrike Kriener) feels left alone with the work at the boarding house. Nevertheless, Marie secretly organizes a surprise party for Mona's birthday, which causes further conflict.
To make matters worse, Mona's arrogant friend Chiara (Ann-Kathrin Kramer) comes to visit and Marie can't stand her. But it soon becomes clear that a personal stroke of fate has brought Chiara to the North Sea, giving all three women food for thought.

Will the two quarrelling sisters Mona and Marie get together and make a success of the boarding house together, or will the stress divide them for good?