Four sisters decide to kill their hateful brother-in-law Jean-Claude and release their beloved sister from his grasp. Nine months later, a pair of bumbling insurance investigators look into his death because they can't afford to pay out.
Eva and Birgit join forces planning to kill Jean-Claude in a fire. They lure him to his chalet in the mountains. In the present day, Bekka begins dating one of the insurance investigators after mistaking him for a funeral director.
The sisters' next plan is to poison Jean-Claude's favorite meal, liver, so they ask Veerle, the nurse in the family, to help. Veerle refuses to get involved, that is until Jean-Claude catches her making out with her lover.
The sisters are having love trouble. Eva's crush turns out to be gay, Veerle's husband is becoming suspicious, and Goedele's sex life is deader than her husband is going to be if the sisters' latest plan (a staged suicide) works.
Bekka joins the conspiracy and comes up with a plan to electrocute Jean-Claude which leads to a nighttime operation and a street-wide blackout. In the present day, Bekka finds out Matthias is not a funeral director.
The sisters' newest plan involves a family paintball outing and a frozen pellet but a mix-up with masks leads to tragedy. In the present day, the DeWitts push for an autopsy on Jean-Claude while Matthias tries to make up with Bekka.
After his supposed suicide attempt, Jean-Claude becomes suspicious that someone is out to kill him so the sisters decide to hire a hitman. They also hire a private detective to cover their tracks which leads to fatal confusion.
Bekka comes up with a plan to freeze Jean-Claude to death in a freezer. Meanwhile, Goedele tries to find herself a hobby which leads her to get into debt with the Chinese mafia and throw a party no one shows up for.
Jean-Claude is dead but who killed him? Was it Roger the paedo or the Chinese Triad or his voyeuristic neighbors? Maybe it really was an accident or a suicide? Or perhaps one of the sisters acted alone.
Jean-Claude gets Eva fired to get a promotion, but a flashback reveals that that is nowhere near the worst thing he's done to her. After the disastrous results of their last plan, the sisters agree not to try to kill Jean-Claude anymore.
