THE GUARDIAN (SEALs Beyond Battlefields book 1) was originally included in the NY Times and USA Today bestselling SEALs of Summer 2 boxed set. 

Corpsman Luke Carter quit the SEALs to take care of his chronically ill daughter and now battles for a cure with The Guardians—a secret philanthropic organization that funds medical trials. To save costs, he must close a failing clinic in Haiti where a compassionate doctor fights to save her patients. Beautiful and strong, she touches his battered heart, making it feel something that died in him long ago—love. But time is a ticking bomb and their world is about to be ripped apart. 

Look for characters from the SEAL EXtreme Team series to play small supporting parts in the book.