Undercover wolf - Linda O. Johnston (Alpha Force #4)

Danger and desire collide in this race against time…

PI Quinn Parran's new mission is to join Alpha Force, a unique military team of shapeshifters, and use their new elixir that will enhance his shapeshifting abilities. But with Sergeant Kristine Norwood, each shifting experiment sparks a volatile primal passion. And when Quinn's brother vanishes on his honeymoon, he must join forces with Kristine and go undercover as newlyweds to investigate.

While Kristine is attracted to the ruggedly handsome Quinn she isn’t about to get involved with a shapeshifter—until their quest becomes more dangerous. Now they must cross the divide between shifter and human, because every minute they’re apart brings the threat closer.