It's a continuation of Season 2. The show was on a hiatus since Dec. 15 when 2-13 Earthlings Welcome Here aired.
Last night's was 2-14 The Good Wound.
A site I usually use is Epguides
http://epguides.com/SarahConnorChronicles/
If you have iTunes, the fall finale (#2-13) is available through
here.