Start with an Event

I just finished reading Compound by S.A. Bodeen. This is the opening scene:

My world ended with a bang the minute we entered the compound and that silver door closed behind us. The sound was brutal. Final.   .   .   .   My fists beat on the door. I bawled. The screaming left me hoarse.

In the next few pages the book explains that Eli's family is in an underground shelter but his twin brother Eddie and his grandmother didn't make it. Eli's father, mother, and sisters Lexie and Terese managed to get safely inside within the forty minutes needed to survive.

The world just ended with a nuclear explosion. Eli's family was safe only because of the compound. Eli's father (a billionaire) had prepared them for this day and made provisions to help them survive underground for the next 15 years.      

Eli was forced to live with the fact that he caused Eddie's death. Eli had talked him into sneaking into their grandmother's car. She didn't make it back to the compound in time to get to safety in the shelter. Now Eli had to spend each day knowing his brother, his twin died because of him.