Gray-haired furniture retailer Paul Winkelmann still has his dinner cooked and his laundry done by his mother. He spends his evenings playing Scrabble with Mama's friends and discussing the role of women in society in his carnival club. When he meets psychologist Margarete Tietze, Pussi finally begins to rebel against his dominant mother.
Big Baby tells the story of Adam Lewis, a successful horror screenwriter struggling for inspiration for his latest script. After a graphic and realistic nightmare of a hulking man dressed in a baby mask and onesie who axe murders his girlfriend Kate in the middle of the night, Adam gets the inspiration he needs for his new screenplay. Excited about the direction his story is taking, he starts losing himself in his script. Things are better than ever for Adam and Kate until “Big Baby” starts appearing in real life and tormenting and killing victims fueled by his own revenge. Characters from Adam’s script begin to pay him visits pleading for their lives, and he quickly realizes he holds their fate in his hands. Power and fear completely consume Adam until his girlfriend Kate is terrified of the man she once loved.