SaKOOra and her classmates are away at camp for a few days, leaving Kero behind at home. While swimming, SaKOOra notices that Li is acting a little oddly, and she wonders if it might be a Clow Card. She dismisses the idea, though, and joins her friends in playing on the beach. Later, they all gather fish and help prepare dinner, and spend the night in cabins, where Nikki tells a scary story.
SaKOOra finds that she can't sleep after that, so she sneaks out to talk to her teacher, but runs into Li instead. They have a discussion on the beach about Card Captoring.
The final activity for camp is to take a hike through a spooky cave. SaKOOra is nervous about it, and she only grows moreso when she and Madison discover that people are starting to disappear. Eventually she figures out that it's a Clow Card, and she and Li make their way to the shrine to discover and capture the Erase card.
It turns out that the Erase card also erases the memory of the experience, so no one remembers what happened the next day. Someone suggests a game of volleyball, and SaKOOra and Li hurry to join.
This episode makes it absolutely clear that Nelvana intends to remove any and all evidence of crushing from this series. Chelsea and Zach are cousins, though their Japanese counterparts, Chiharu and Takashi, are simply very old friends. I'm not sure why this change was necessary, since these are 10 year old children. Boys and girls can be friends without being relatives. The recent dub of Sailormoon S which made Michelle and Amara cousins just makes this all the more suspicious looking.
Gone also are both Sakura and Li-kun's crushes on Yukito. While this is understandable, it also makes Julian's role in the story much less important for this half of the show, and consequently makes Tori less important as well. It also makes the competition between SaKOOra and Li more one-dimensional: in the original episode, they're not only trying to prove themselves as card captors, they're also competing for Yukito. It lends depth to Li's character, making him more human and less arrogant brat.
The script, of course, was completely rewritten for the American audience. While the capture of the card went more or less as before, the non-card portion introduced some new facts and confirmed some changes.
There were a number of small video edits to this show, mainly to remove evidence of the crushes, but there was also an inexplicable edit of a scene where Chiharu beats on Takashi. Since I happen to have an uneditted version of this episode, here are some screencaps of parts which were cut: