Growing up in foster care, Sara's closest emotional support was her slave, Gilbert Grissom. He passed onto her his love of science, and she pursuaded her foster parents to allow him to be trained in forensics. Years later, they live apart, although she is still legally his owner. When he calls and asks her if she'll come to Las Vegas after the death of a rookie, she agrees. (Their relationship can be either as friends/siblings, or lovers; I'll accept any pairing het, slash or femslash, or gen if you prefer.)