According to the interview with E! Online with Dushku and Whedon, Dollhouse is the story of Echo, a programmable human plaything:

"Echo (Eliza Dushku) [is] a young woman who is literally everybody's fantasy. She is one of a group of men and women who can be imprinted with personality packages, including memories, skills, language--even muscle memory--for different assignments. The assignments can be romantic, adventurous, outlandish, uplifting, sexual and/or very illegal.

"When not imprinted with a personality package, Echo and the others are basically mind-wiped, living like children in a futuristic dorm/lab dubbed the Dollhouse, with no memory of their assignments--or of much else. The show revolves around the childlike Echo's burgeoning self-awareness, and her desire to know who she was before, a desire that begins to seep into her various imprinted personalities and puts her in danger both in the field and in the closely monitored confines of the Dollhouse."