Smallville episode 8.08 “Bloodline“
Airdate: November 6, 2008
Clark Kent and Lois Lane accidentally traveled to the Phantom Zone and found Kara in the forbidden land. Kara has a portal but she refused to leave the Zone, because “she didn’t want to make the same mistakes that Clark did”.
Interesting of Kara to say that. The last time Clark Kent escaped the Zone, several other wraiths escaped with him back to earth and they wreaked havoc for one whole season! Bizarro was the worst of those Kryptonian enemies. Maybe that’s what Kara was trying to prevent.