At the beginning of their stories, both Gwendolen and Daniel are striving to move up in some way. We might as well mention now that Daniel's rags to riches story isn't just about suddenly becoming rich in terms of money – though he does end up with money at the end. Let's not jump ahead of ourselves, though. Daniel's rags to riches story involves going from a lack of self-knowledge to an abundance of it. Gwendolen's story is much closer to traditional rags to riches story based on financial struggle.
So, now that we've said that, let's delve in a little deeper. When the story begins, Gwendolen has gambled away all of her spending money, which doesn't seem like a big deal to her until she finds out that her family has absolutely no money left as the result of a bad business deal. Daniel, meanwhile, has no idea who his real parents are. Though he suspects that his guardian Sir Hugo is actually his dad, it seems unlikely that Daniel can inherit any of Sir Hugo's fortune after he dies.
Even though Gwendolen initially decides she can't marry Grandcourt because of the whole Lydia situation, she has to admit that getting hitched is the best way to pull her family out of poverty. While she doesn't get the best vibes from Grandcourt and feels pretty guilty about the whole Lydia thing, overall she feels like she's probably done the best thing by marrying Grandcourt. Daniel, in the meantime, feels that he's doing something good by saving Mirah and helping her to find a safe place to live. He starts to become curious about Judaism and finds a new outlet for his energies and interests.
While Daniel hopes that he can find Mirah's family, his concerns about his own identity make him worry that it might not be the best thing to try to dig up any new information about them. He feels a pang of sadness when he thinks about where he belongs. Gwendolen, in the meantime, is starting to realize that Grandcourt is a big jerk who enjoys the fact that he has so much power over her and her family. She is just trying to do the best thing for her family, but starts to think it would have been better to just be a governess and be single.
When Grandcourt drowns, Gwendolen is finally freed from his clutches. That said, that doesn't mean that she feels all that great. Gwendolen's final ordeal is twofold: she has to deal with her feelings of guilt over his death, and she also has to decide whether or not to accept the money that Grandcourt left her. Daniel, meanwhile, is released from his world of secrets when he finds out his mother's identity and meets her in Genoa. He has to deal with the fact that she doesn't want to have anything to do with him beyond assuring him of the money he will inherit from his dead father and telling him about the chest that his grandfather left to him.
Daniel receives his grandfather's chest. He goes home equipped with a whole new knowledge of who he is. He also finds out that Sir Hugo has been hanging onto Daniel's inheritance from his deceased father, so Daniel does end up with some money at the end. Oh, and he gets the girl. Daniel's just cashing in all over the place. Gwendolen, meanwhile, decides to keep the inheritance from Grandcourt and moves back in with her family, determined to start her new life as a better person.