Under the Radar by Fern Michaels
 
Under The Radar (©2009)
Rules of the Game Series #6

Fern Michaels

Just returned to their mountaintop hideaway in the wake of their latest successful mission, the seven fearless friends have barely had time to enjoy a celebratory dinner with their mentor, Charles Martin, when they're embroiled in a new adventure.
      In the middle of the night, the Sisters are awakened by an alarm bell. Suspecting intruders, they run to the compound, only to see Myra and Charles rushing towards a helicopter. Within seconds, the two have flown away, with no explanation besides a mysterious note from Charles: I've had an unexpected personal emergency. I don't know when or if I will return. Still reeling from this turn of events, the Sisters receive an urgent call from retired justice Pearl Barnes, who's just rescued fourteen pregnant teenagers who belong

to a highly secretive polygamy sect.
       Now, with Charles and Myra missing, the remaining members of the Sisterhood must rally together to save the girls. This time, the Sisters are doing it by themselves and everything is on the line...