So, we go back now to see what Tom and Becky have been up to for the past three days; we already know about the graffiti and their being lost and all that, but here's how it happens:
Tom happens upon a little waterfall in the cave, and figures out that, just behind the water, lies a passage leading down deeper into the cave. He takes Becky along with him into the newly discovered area.
They enter a big cavern with stalactites hanging from the ceiling, find a spring covered with crystals, big columns made up of stalactites and stalagmites joined together.
Out of nowhere, they're swarmed by a bunch of bats; Tom manages to get himself, and Becky, into the safety of another corridor, but the kids have to keep running from the creatures.
Having eluded the bats, they find themselves in a cavern with a big underground lake, so big that they can't see from one end to another in the darkness.
Tom decides it's best for them to take a breather at this point. Becky and Tom get to talking about how tired they are and how, well, gee, they haven't heard anybody else in a while. They decide to try and find another way out of the cave – they don't want to deal with those pesky bats – and Becky says, just before they head off, "I hope we don't get lost. It would be so awful!" (31.9). Sorry, Becky, but you already are.
So, basically, Tom and Becky start running around in circles and Tom starts trying to holler for someone. This scares Becky, who gets extra mad when she finds out that Tom didn't make any marks to help them get back to the entrance. At this point she loses it and falls to the ground, crying.
Tom does his best to comfort her, and the two set out again soon enough, though this time they're forced to use only one candle at a time in order to economize. This is not a good sign.
By and by the kids get tired, and before you know it, Becky and Tom are sitting again. Becky even manages to fall asleep. This doesn't help things; she's angry with herself when she realizes she's nodded off at such a stressful time.
At this point they've been in the cave so long that they don't even know what day it is. They wander a bit more, then sit down again for a piece of "wedding cake" – apparently Tom and Becky got "married" at the picnic. After this nice interlude, Tom gives Becky some bad news: they're on their last candle. Oh, and then they realize that, because of Tom's little "I'm sleeping over at the Harpers' house" ruse, no one will know they're gone until at least Sunday.
Suffering and darkness ensue – the last candle burns out – until, all of a sudden, they hear something in the distance. The two run toward the noise, but are soon stopped from continuing by a large and potentially deadly chasm in their path. Tom attempts to yell and get the searchers' attention, but he gets no response.
Tom decides upon a new course of action. He and Becky retreat to the spring; he gives her a piece of "kite-line" to hold and sets out with the other end in his hand.
Soon after he sets out, Tom sees a hand holding a candle. He yells in joy until he realizes that the hand in question is…Injun Joe's!
The shout is enough to scare Joe away, however, and Tom is able to make it back to Becky unharmed; he neglects to tell her what he's just seen, however.
After Becky and Tom get a bit of rest, Tom sets out again to find a way out.