The US import only attracted 390k (1.7%) from 8pm - down from 523k last week. The series had originally premiered to 757k.
Elsewhere on the multichannels, Mad Men appealed to 39k (0.2%) on Sky Atlantic. In the same 9pm timeslot, The Vampire Diaries earned 437k (1.8%) with a further 134k (0.8%) on timeshift, while Alcatraz entertained 459k (1.9%) on Watch.
The terrestrials saw BBC One's The Syndicate dominate with 5.53m (23%) from 9pm, beating ITV1's The Mighty Mississippi, which grabbed 2.63m (10.9%) and 242k (1.5%) on +1.
Earlier for ITV1, Countrywise Kitchen was seen by 2.35m (10.6%) from 7.30pm, with a celebrity special of Who Wants to Be a Millionaire? winning 2.41m (10.5%) afterwards (+1: 104k/0.4%).
BBC Two aired Hairy Bikers' Bake-ation (2.95m/12.9%) and Meet the Romans with Mary Beard (1.78m/7.4%).
Channel 4's The Undateables was watched by 2.28m (9.5%) and 417k (2.6%) on +1. It was preceded by Supersize v Superskinny, which averaged 1.7m (7.4%) across the 8pm hour (+1: 257k/1.1%).
CSI continued strongly for Channel 5 with 1.77m (7.3%) and 145k (0.9%) on timeshift. Rory McGrath's Pub Dig managed 802k (3.5%).
Overall, BBC One won primetime with 24%, far ahead of ITV1's 12.9% (+1: 0.7%). BBC Two came third with 8.5%, beating Channel 4's 6.4% (+1: 1.2%) and Channel 5's 4.9% (+1: 0.3%).
BARB ratings data supplied by Attentional