Stef Foster and Lena Adams, a lesbian couple, have a family of adopted, biological, and foster children. Mariana and Jesus are adopted 15-year-old twins and Brandon is Stef's 16-year-old biological son from a previous marriage. Everything is going fine in the house until Callie and Jude arrive. 16-year-old Callie and her 12-year-old brother Jude have been in many different foster homes, but when they are placed with the Fosters, things begin to happen. In this series, the Fosters will deal with many different issues: hook-ups, break-ups, romances, and important life lessons.

Callie and Mariana Foster embark on the next phase of their young adult lives in Los Angeles.