Brad (Will Ferrell) is a radio manager. After he met a woman named Sarah (Linda Cardellini) and fell in love with her, he had two lovely stepsons, Megan (Scarlett Estevez) and Dylan (Owen Vaccaro). Since then, Brad has a new goal in his life memo-to be the best stepfather in the eyes of the two children. However, the existence of a man makes this goal seem out of reach. That man is Sarah's ex-husband, the biological father of the children, Marlon (Mark Wahlberg). This man who looks unkempt and idle all day long has repeatedly harassed Brad's life. Although Marlon looks so unreliable, his appearance is always warmly welcomed by the children.