We know that season three will cover Penelope and Colin's love story, which Quinn wrote about in her novel "Romancing Mister Bridgerton." But the soon-to-be lovers are in quite a different situation in the TV show than they were in the books. Book readers didn't find out that Penelope was Lady Whistledown until book four, while TV watchers have known since season one. In the books, Penelope has kept everyone from finding out the truth. In the show, Eloise (Claudia Jessie) knows, and their friendship has fallen apart because of it.
In the books, Eloise doesn't learn Penelope was Lady Whistledown until well after Penelope and Colin are wed. The TV show also added the season one plot involving Colin, Marina, and Penelope, which doesn't exist at all in the books. All this is to say that how the show chooses to get Colin and Penelope to their happily ever after will be a surprise for both book readers and casual viewers alike.
One aspect of the story fans don't have to worry about is the book's controversial Penelope glow-up, which leads to Colin seeing Pen in a romantic light. In the book, this change is mostly attirbuted to Penelope losing weight. Coughlan revealed to Variety in June 2022 that the show's version of the character's glow-up will be about her coming into her own strength, and the only major change in her appearance will involve her over-the-top dresses being dialled back a bit. "I think the glow up is going to be more to do with the costumes," Coughlan said. "I think it's not going to be like this insane physical transformation."
There's also the chance we'll see more of the other siblings' love lives this season, too. With news that the show has recast the role of Francesca, it's possible it will include the story of Francesca meeting and marrying her first husband, which is not the plot of her novel "When He Was Wicked." Plus, "Queen Charlotte" set up that Lady Violet will be looking for some love — and lust — of her own this time around.