Analysis: What's Up With the Ending?
At the end of our story that takes place in the way-back 19th century, Winnie dumps her immortality juice on a toad and calls it a day. Hey, she can always go back to the spring for more, right?
Lucky for us (and our poor books which would otherwise be ripped to shreds), that's not the last we hear of Winnie. Out handy dandy epilogue reveals that Winnie never did go back. She didn't drink from the spring, she didn't become immortal, and she didn't join the Tucks.
It looks like Winnie took Tuck's words to heart and decided that the benefits of immortality weren't worth the sacrifices that it would require. This is bittersweet for Tuck: because the spring is gone (thank you, natural disaster), the Tucks are officially on their own forever. And we mean forever.
Little do they know that the middle-of-the-road toad they save could have joined them on their journey.