All the HERO Force novels can be read as standalone stories.
Trevor "Hawk" Hawkins and Olivia Grayson are finally going to marry, but she's finishing up a film before they say "I do." When someone starts stalking her, Hawk must go overseas to protect the woman he loves—but a ghost from his past may draw him away from HERO Force forever.
This is a novella, not a full-length book.