Felix Murot (Ulrich Tukur) has hardly arrived on vacation and is having a good time with a glass of wine in the garden of the local restaurant when the irritable waitress slams a knuckle on his table that he hadn't ordered. She mistakes him for Walter Boenfeld (also Ulrich Tukur), a married used car dealer who sits at the other end of the restaurant garden and waits in vain for his food. Murot goes in search of the actual owner of the knuckle and gets to know Walter, who resembles him like two peas in a pod. Inspired by this strange encounter, the two different gentlemen spend the evening together, drink too much and talk about life in the sauna.
When Murot wakes up the next day, hungover on Walter's hammock – and thanks to a drunken swap in the clothes of his doppelganger – the inspector has to realize that Walter was killed on the country road that night. Was it his wife Monika (Anne Ratte-Polle), who Walter claimed last night that she wanted to kill him? So Murot decides to temporarily leave his everyday life as a detective behind, to immerse himself in the life of his twin and investigate undercover. Murot falls more and more in love with the thought of leaving his old life behind. But Magda Wächter (Barbara Philipp) doesn't let her boss get away that easily.