When Dusty (Mark Wahlberg) and Sara's (Linda Cardellini) little girl Megan says she used to love Christmas, but now that it's divided between two homes, she doesn't love it anymore, Dusty and stepfather Brad (Will Ferrell) join forces to provide their kids with the perfect Christmas.
But their newfound partnership is put to the test when Dusty's old-school, macho dad Kurt (Mel Gibson) arrives, much to Dusty's dismay. His memories of his dad are mostly about being neglected by him. When Kurt suggests renting a big house for the entire blended family to spend Christmas in the mountains, Brad isn't impressed, although the rest of the family is all in. Meanwhile, Brad's ultra-affectionate and emotional dad Don (John Lithgow) also arrives for Christmas, much to the delight of the children, but Dusty senses something's not right when it turns out Brad's mom has decided not to join him.