The last time I saw my little brother's best friend was before I'd left for boot camp when she still had pigtails and braces. Now Samantha Kohler is all grown up and home for the summer with an offer I can't refuse. Twelve weeks of casual fun? Hell yes. The problem is I've only ever had serious relationships and don't know how to do no-strings-attached. But Sam has plans to complete her PhD and is moving out of state at the end of...