It appears as if CBS is really stepping out of their usual modus operandi with the series because tonight's episode was very heavily serialized, feeling much more like, say, FOX's Fringe or the short-lived Vanished than your typical CBS procedural.
I don't think it's ever going to become a straight-up serialized drama, but the series is definitely a different animal for CBS, and is definitely 'must watch TV' because of that fact (at least IMO).
It also doesn't hurt that the characters and actors are phenomenal and have great chemistry together.