On March 31, 2013, ABC ran an “enhanced rerun” of episode 2×09 Queen of Hearts (original air date Dec. 2, 2012).
This is the episode where Regina sends Hook to Wonderland to kill Cora, but Hook ends up doing Cora’s bidding instead; where Emma and Mary Margaret use magic squid ink to escape from Rumpelstiltskin’s cell, then fight off Cora and Hook on the shores of the lake/portal and re-enter Storybrooke via the wishing well — where Regina, at the very last minute, listens to Henry’s pleas and removes the dark magic she and RumpelGold had cast to kill whoever would come through.
The “enhanced” part of the rerun was a text box at the bottom of the screen. The tradition of enhanced reruns started with LOST, where the text notes revealed some of the obscure connections between events — from different episodes and different seasons — that even hard-core fans may have missed. The text notes in the Queen of Hearts rerun, though, were more basic. They seemed to be aimed at new viewers, filling in some of the background of the story for people who hadn’t seen the show from the beginning.
You can watch the enhanced version here: