Gen Watanabe Timeline and Summary

Gen is at the birthday party for his employer, Mr. Hosokawa, when it's taken over by terrorists.
Gen volunteers to translate, since no one else seems to be able to do it.
Gen pretty much becomes the translator for everyone there because he's the only one who knows enough languages. Pretty impressive, even if it's also kind of scary.
Carmen asks Gen to help her learn reading, writing, and languages. That's a lot to teach.
Gen begins teaching Carmen.
Carmen kisses Gen, which begins the romance they've both been wanting.
Gen and Carmen help Roxane and Mr. Hosokawa spend the night together. Which helps spur on the two of them to spend the night together.
Gen and Carmen talk about a life together after the crisis, and Gen continues teaching Carmen. These people are living in denial, but they don't want to admit it. Which, um, is what denial is.
Carmen is shot by the invading government soldiers who come to free Gen and the other hostages. Can't deny the reality anymore, now.
Gen marries Roxane Coss not long after the hostage crisis ends. It may seem like a weird move after Carmen's death, but it seems to make sense for them. Probably.