Stef Foster is a tough but kind police officer, even if she’s not what would normally be described as “maternal.” A divorcee now in a happy lesbian relationship with Lena, her soulmate and very significant other, Stef is the biological mother of Brandon and the adoptive mother of two kids out of the foster system. A loving but stern disciplinarian, Stef has an agreement with Lena that they won’t foster any more kids until Brandon has left home. When Lena opens their home to the abused, defiant Callie, Stef is initially upset. But she soon realizes that Callie is a broken girl who needs mending – and she and Lena may have no choice but to take her in.