Having accorded the first episode of this new season of “Cardinal” an exemplary rating, does the remainder of the first half of the season measure up? I’m happy to report that it does. In fact these three episodes form a seamless whole of growing dread. The initial murders mystify even more but John Cardinal and Lise Delorme take a few steps forward, and then the killers introduce themselves to us, and they’re as frightening as all the villains of the series have been. And in the meantime Cardinal pursues his hidden project concerning his dead wife. It’s a heady, unremittingly bleak brew that pushes the viewer to continue, if only to relieve the tension.