Lena Adams and Stef Foster are the Fosters, an interracial lesbian couple who are married and living in the Mission Bay area of San Diego, raising Stef's biological son along with adopted twins and foster children. Lena is a charter school vice principal. She decides to take in Callie, a "troubled" teen with an abusive past whose ways will turn the family lives upside down. Stef is a tough yet kind police officer who isn't as eager to add to their family. Lena tries to introduce new children to the family, not always with Stef's previous knowledge.