"I've Got You Under My Skin," the second episode of Charmed , establishes the series' core "Power of Three" dynamic by focusing on personal consequences and the rule against using magic for personal gain. The episode introduces recurring villains Rex and Hannah, while the sisters vanquish the youth-stealing demon Javna. For more in-depth insights into this episode, read a detailed discussion at Reddit www.reddit.com/r/charmed/comments/9q5ppr/charmed_retrospective_discussion_ive_got_you/.