Cosette and Marius meet one another in Cosette's garden whenever they can, but you can stop clutching your pearls: they love each other so much that neither of them ever thinks about sex. Uh-huh.
Cosette also finally takes the opportunity to tell Marius that her true name is Euphrasie.
One day, right after Marius leaves the garden, a group of men led by her dad Thénardier comes by and talks about breaking in and robbing the place. But Éponine shows up and tells them she'll scream if they make any effort to rob the house. They don't even realize that the place belongs to Jean Valjean. They've just heard that there's money inside.
Eventually, the men give up and leave.
Meanwhile, everything is going well for Cosette and Marius, so you know Victor Hugo has to throw a wrench into their plans. And here it is: Cosette tells Marius one day that she and her father are going to go to England and she doesn't know when they'll be back. Marius is heartbroken.
Marius says he'll need a day to himself in order to figure things out and writes down his address for Cosette.
Now we look back in on Monsieur Gillenormand, who has spent the last several years brokenhearted and lonely after the departure of Marius.
Then one day, out of the blue, Marius shows up at Gillenormand's front door. He wants his grandfather's blessing to marry Cosette. But Mr. Gillenormand was hoping that Marius was coming back to grovel and beg for money. He's so stunned that he speaks harshly to Marius and declares that he won't give Marius permission to marry.
Eventually, the argument calms down and Mr. Gillenormand asks Marius to tell him more about the girl he (Marius) wants to marry. They chat for a bit and Mr. Gillenormand gets a kick out of living vicariously through his grandson's love affair.
When he tells Marius to just make Cosette his friend with benefits instead of marrying her, though, Marius gets super offended and storms out of the house.
Mr. Gillenormand runs to the window and calls for Marius to come back. But it's too late. The boy is gone. The man sinks back into his chair, crushed by the thought that he'll never see Marius again.