I love this episode, better than the first part, SO MUCH better.
The Source sends Shax to kill Prue, and now the sisters seek revenge for the Source. However, without the Power of Three, the sisters can do nothing. Unless they convince their half-sister, Paige Matthews, before the Source kills her.
Cole Turner, used to be an evil demon, and also Phoebe's boyfriend, sacrifice himself to save the sisters (Luckily he survive). Things don't go well to Paige, when her boyfriend Shane, has been possessed by the Source. And now the Source is using him to manipulate Paige in order to kill the remaining Charmed Ones, Piper and Phoebe Halliwell.