Three Act Plot Analysis
Dorothea's marriage to Casaubon, his death, and her discovery of the codicil in his will forbidding her from marrying Will Ladislaw.
ends when Dorothea walks in on Will Ladislaw and Rosamond Lydgate and thinks they're having an affair.
Everything gets resolved – Rosamond explains it all to Dorothea and leaves Will free to marry Dorothea. After Dorothea gives up her fortune.