In my hunt for decent TV SF series I came across some favourable mentions of Dollhouse, so I put it on my view list.
The MacGuffin for this series can be summed up as "mind wipe and personality transfer". Criminals faced with a long jail term are given the option of volunteering to spend five years working for a secret corporation that removes and stores their personalities and substitutes those recorded from other people with specialist skills. The criminals (known as "Actives" or "Dolls") are then sent out on missions which range (in the first few episodes) between acting as a good-time girl for a rich man, a bodyguard in the guise of a pop singer, a master safe-cracker and a hostage negotiator. At the end of the mission their borrowed personalities are wiped and they are left as robotic blank slates until they are prepared for their next mission.
The principal Doll on which the series focuses, played by Eliza Dushku, is given the code name Echo. This part is a gift to an actor since she is on screen much of the time, playing dramatically varying roles (rather like Orphan Black in that respect), and Dushku is a convincing heroine. There are strong supporting roles, especially Olivia Williams as the person in charge of the Dollhouse, Harry Lennix as Echo's "minder", and Tamoh Penikett as FBI agent Paul Ballard who is certain that the Dollhouse exists, although his colleagues disagree.
It soon becomes clear that the mind wipes are not entirely effective: Echo appears to be slowly recovering some of her memories and personality, while one of the Dolls (Alpha) accidentally recovered the skills of all of the people he played and went rogue, threatening the Dollhouse. As the series continues, the plot switches away from the Actives' missions and becomes more complex. It focuses on the Dollhouse organisation itself, tensions within the management, and its real purpose, along with Agent Ballard's attempts to discover what is going on.
Compared with other series, Dollhouse is a slick production with a typically American glossiness about it. In contrast, the Canadian Orphan Black is grittier and darker but also much funnier, with the humour balancing what would otherwise be a rather grim tale. Dollhouse may lack much humour but the premise is intriguing and well-enough executed to hold the attention, and the script is intelligent. One long scene sticks in the mind in which Ballard confronts a rich man who hires Echo once a year to play "house"; Ballard is contemptuous but the rich man explains his motives and challenges Ballard's, and the viewer is left feeling rather sympathetic. I do like drama which goes beyond the usual Manichean good/evil contrast to show that the bad guys are not always evil and the motives of the good guys are not always pure.
The final episode of Season 1 – Epitaph One – is entirely different. It jumps forward to 2019 when the world is in chaos due to the uncontrolled spread of the mind-wiping technology. I understand from the Wiki summary that Season 2 then reverts to the present-day timeline to reveal how this catastrophe occurred, before the finale of Epitaph Two which jumps again to 2020. However, at the time of writing, Season 2 has not been released on DVD in the UK.