Marianne improves, is actually nice to Colonel Brandon and Mrs Jennings, and goes home to Barton, where she endeavors to be less of a selfish diva. She sets herself a course of study involving reading and regular exercise (going overboard, as is her usual MO), apologizes to Elinor for having been such a mess, acknowledges that if she had died it would all have been her own fault and . . . we're ready for the next chapter. No. Really.
But the chapter does contain one of my favorite exchanges between the sisters:
Elinor: "Do you compare your conduct with his?"
Marianne: "No. I compare it with what it ought to have been; I compare it with yours."