What happed to Sae Young that made her stay home for two years?

Sae Young's had an appalling run of bad luck since she moved to the United States from South Korea with her husband. At first, though, things were going quite well. The dry-cleaning business that Sae Young started with her husband was becoming pretty successful. Sae Young enjoyed the experience of working alongside her husband to realize their dreams of making it big in America.
Sadly, all that changed when Sae Young's husband died from a heart attack at a very early age. But even worse is to follow. One day, Sae Young is beaten up and robbed at her dry-cleaning shop. It's a deeply traumatic experience, as we might expect, and on top of everything else, it causes Sae Young to retreat from the world. She just can't handle being around people anymore. So she shuts herself away, staying at home for two long years, away from her friends, her neighbors, everyone.