Chris-Crossed, I Dream of Phoebe, and this episode make Season 6 before the finale. I am surprised this episode is not rated among the best episodes of Charmed. It should be. Once again we have a darklighter after Leo. Except this time, with the help of a certain elder, the darklighter has teleported Leo and Piper into the ethereal plane where they don't have their powers. At the same time, we have the ticking clock winding down on Chris; Leo and Piper must renew their love for each other and consummate it, or Chris ceases to exist. No pressure.
The climactic scene between Piper and Leo is well-written and wonderfully acted. Holly and Brian have always had a fabulous chemistry between them. Frankly, it is about as moving a scene as you will find on Charmed, and it never feels contrived. More like, it is affirmation of what you already know; you know these characters love each other, and their separation is a sham.
That is not the only great scene in this episode. We have the final scene, which reveals Gideon as the central antagonist for the remainder of the season. Very effective.
We also have Leo and Gideon's talk on the bridge. Here we finally see all the sorrow and agony out of Leo that we didn't see at the end of Oh My Goddess. This is what we should have seen from the beginning. If the writers insist on Leo being away from Piper, I can understand why, but that doesn't mean Leo has to like it.
Lastly, we have the fantastic scene between the sisters as Phoebe and Paige reveal to Piper that Chris is her son and she is now pregnant with him. Holly, Alyssa, and Rose are amazing here, as usual, especially Holly, who obviously is a little more pregnant than she should be but no one cares. That awesome scene ends with Chris showing up and Piper finally seeing him as her son. It is a top 10 Charmed moment, easy.