Witchblade is a show about a NY cop, Sara Pezzini (Butler) who acquires the talisman, and how she 'uses' it. There are others who wish to possess the Witchblade, or control the woman who posesses it so while she's learning about it, its powers, and her role, she's got to defend herself, and do her job.
http://www.epguides.com/Witchblade/
The reason they're 'redoing' it is because at the end of last season everyone, including Pezzini, either died or was dying so she was able to use the 'once in a lifetime' power to reverse time, to a point before her partner died in the season opener, so essentially, they're redoing the first season.
I'm not doing it justice, but that's a very high overview.