At the beginning of the 2003 Iraq War, Private Matt Ocre (Nicholas Hoult), a young civil affairs soldier with the Army Reserves slams his hand in the door of a Humvee in an attempt to get sent home. Narration reveals that he enlisted in July 2001, in order to get money for college.

Why does ocre get sent home in Sand Castle?

He joined the Army Reserve before 9/11 to pay for college tuition, never suspecting he'd be tasked with bringing democracy to the people of Iraq. After around 10 minutes or so, and she sent me home.

What is the ending of sandcastle?

The book ends with the baby born on the beach, now grown, alone and building a sandcastle.