Rizzoli and Isles are back again and his time its Isles who is the main character and she is far away from Boston. Maura has gone to a pathologist convention in Wyoming where she meets an old classmate from university. He is also at the conference wih 2 friends and has teenage daughter. They convince Maura to join them on a trip to go cross counry skiing before heading home. Her friend Douglas is the instigator of the trip is rather impulsive and did not check weather forcasts before heading out. Running into snow on the trip and following the GPS instructions sending them on the "shortest" route but not the best gets them suck miles from nowhere. Seeng a sign on the road past where they ended in the ditch the hiked past a barred road and came on a small settelment but found no people and doors unlocked, windows open and uneaten food on the table. Added to that there was no electricty or other modern convienences in any of the houses. Thus begins a trying, exhausting time for Maura as she fights for survival in the face or threats from what appears to be a cult and hostile local law enforcement until Rizollli and friends travel west to find out why she has not returned to Boston as expected.