Although unplanned teenage pregnancies have dropped by more than half since the early 1990s, nearly one in four girls get pregnant by age 20. TLC explores the complicated issue of teen pregnancy in `Unexpected' by focusing on three pregnant teen couples and how it affects their families. Cameras capture the various stages of each pregnancy and the first few weeks of parenthood. In each story, the pregnant couple is entirely unprepared to have a child, and it falls upon their parents or grandparents to help. Roles are blurred and tension begins to mount between the families, as everyone has their own ideas for what is best for the young parents and their child, from where they will live to when (or if) the couple should get married.