IRREPLACBLE attempts to raise an important question, "What is the family?" and "Is the family still important in today's society?"; The host of this movie (New Zealand Focus on Family Executive Director Tim Sisarich) attempts to identify this motto: "If the family fails, society will fail; it is true." He explores the concept of the family with experts from around the world to determine whether the traditional concept of the family is meaningful or actually outdated. If it is meaningful, is the family worth preserving, or even fighting for? On the journey, he hopes to discover why all humans long to be with their families - to be part of something - and what forces cause the breakdown of the family.