A 16-year old vampire discovers she has the ability to withstand sunlight. Sensing an opportunity to round up new victims, her family enrolls her in high school, where her who-cares attitude quickly makes her the coolest girl around.

After moving to The Coterie in Downtown Los Angeles, Callie and Mariana Foster realize that living on their own is not all that it’s cracked up to be.

Une fois leurs études terminées, Callie et Mariana, deux des enfants adoptifs de la famille Adams Foster, s'installent à Los Angeles où elles vont vivre leurs premiers pas d'adultes, entre défis, déboires professionnels, histoires d'amour, et nouvelles amitiés forgées au sein de leur logement communautaire.

Stef Foster, a dedicated police officer, and her partner Lena Adams, a school vice principal, have built a close-knit, loving family with Stef's biological son from a previous marriage, Brandon, and their adopted twins, Mariana and Jesus. Their lives are disrupted in unexpected ways when Lena meets Callie, a hardened teen with an abusive past who has spent her life in and out of foster homes. Lena and Stef welcome Callie and her brother, Jude, into their home thinking it's just for a few weeks, until a more permanent placement can be found. But life has something else in store for the Fosters.

Wie es der Titel bereits andeutet, dreht sich in The Fosters alles um die Familie Foster. Zu dieser gehören in erster Linie die Polizistin Stef (Teri Polo) und Lena (Sherri Saum), eine stellvertretende Schulleiterin. Beide leben mit ihrem biologischen Sohn Brandon (David Lambert) sowie ihren zwei Adoptivkindern, namentlich Jesus (Jake T. Austin) und Mariana (Cierra Ramirez), zusammen in einem Haus in der idyllischen Vorstadt.