Panel 1: We start things off with a smiling, excited Liz responding to something that Dawn has just said by saying "She does? I can?"
Panel 2: We introduce conflict in the proceedings when Liz tells Dawn she's gotta run this by her mother first.
Panel 3: A while later, we find ourselves in the kitchen watching Elly type up some paperwork as Liz tells her that Dawn says that she can go to her cousin's place with them because she has a pool.
Panel 4: Since this is the Sundayverse, Elly doesn't dig in her heels. What she does is remind her to bring a towel and ask if she's got her bathing suit with her. Liz says that she's wearing it.
Panel 5: When Elly reminds her about sun protection, the pool safety rules and wonders if there is adequate supervision, Liz rolls her eyes in frustration as she mutters Uh-huh.
Panel 6: Elly hands her a snorkel, mask and flippers and tells her to share.
Panel 7: After Liz leaves, Elly yells "Be good, be careful and have fun" at the back of her head.
Panel 8: It would appear that Liz forgot to ask what size the pool is. This is because she looks rather a lot like Alix Stone because she's in a kiddy pool with swim fins and diving gear. Unlike Alix, she doesn't appear to be enjoying it because she's wedged in with Dawn and her cousin as the silhouettes of Carol and her sister talk amongst themselves.
Summary: Leaving aside how dangerous them things are, it's sort of obvious that
howtheduck is right about Liz being too old for sight gags like this. Time for April to fool all of us. 
