Which episode in Charmed is the one Paige goes to a different dimension?

In the "Charmed" episode titled "Charmed Again" (Season 4, Episode 1), Paige Matthews travels to a different dimension. In this episode, the sisters face the consequences of their actions, and Paige's journey leads her to discover her own powers and identity as the new Charmed One. This episode marks Paige's introduction to the series after the departure of Prue.