… one of the most emotionally compelling hours the show has ever done. … an hour that plunges headfirst into the moral quandaries and compromises that reside at the heart of the Dollhouse. It doesn't shy away from the queasier questions about what the dolls are doing during their working hours. It asks pointed questions about who has power, how that power is used and the consequences of using power. But at its heart, "Belonging" is an episode that serves as an "origin story" for Sierra, and as such, it's very affecting. …9 p.m. Friday. Fox.