The House of the Scorpion
Ton-Ton is a Lost Boy at the Plankton Factory with a bad case of acne, a speech impediment, and a serious knack for driving a shrimp harvester. You'd be forgiven if at first you thought Ton-Ton is just a jerk who's totally loyal to the Keepers. He does whatever Jorge, a Keeper, tells him to do, and he leads the nightly criticisms of Matt. Not cool.
But everything changes when Jorge turns on Ton-Ton and beats him up in front of all the boys. Ton-Ton can't figure out what went wrong at first, but one thing's for sure: things will never be the same. He soon starts running with Matt, Chacho, and Fidelito, and we begin to see him as a better guy than he first seemed to be.
We might have a hard time squaring this with the old Ton-Ton, but once we learn his backstory, this transformation starts to make a bit more sense. Ton-Ton lost both his parents in Dreamland, or Opium, and only survived because Jorge rescued him from the Farm Patrol. Jorge then convinced a grateful Ton-Ton to stay with him and train to be a Keeper, even though Ton-Ton has a grandmother still living nearby in San Luis. Ton-Ton really struggles with his loyalty to Jorge – he owes the guy his life – but in the end, he decides to make his own choices.
Matt and the others warm up to him pretty darn quick. It doesn't hurt that Ton-Ton is a very useful person to know. He has an in with the Keepers and he's from San Luis, which means he can help Matt and his friends plan their escape. But he doesn't just plan, he acts. He's the one who drugs all the Keepers, which allows the boys to take over the compound. Then he steals the shrimp harvester to drive himself and the others to San Luis. No surprise, then, that he gets the ultimate invite to come help Matt chance Opium at the end of the novel – this is a kid who has learned how to stand up to authority.