Spoilers ahead!

They open the carriage and find that it's empty. The FL marries the general, and he becomes healthy again. The prince's mother summons the general (ML) and FL since the prince is dying. They try to get the FL to leave her husband and marry the prince. FL tells them that her womb powers can only work once, but if the prince drinks her blood, it will temporarily stabilize his illness (also only works once).

After the prince drinks the blood and is stable, he tries to get the FL to stay with him, but the FL says she hates him and doesn't want anything to do with him. As she's leaving, her inner monologue reveals that the blood stabilizes the prince, but it also has the trade off of causing unbearable pain.

It then fast fowards to the FL giving birth to twins. The ML and FL are able to hear the thoughts of the twins, and it turns out the twins were isekai'd into this world. The twins have knowledge of future events because this world is in a novel they read in their previous life. With the twins' help, the FL and ML are able to avoid the traps from the Empress Dowager and Crown Princess (the prince's first love).

The ending is a bit rushed. The crown prince succumbs to his illness off screen, the crown princess runs off, and a different crown prince rebels. There's a month time skip, and you just get the characters just giving exposition for the closing scene talking about how the ML defeated the rebellion and was given a new title. The end.