E is for Emerald — K.T. Tomb

A little vacation is exactly what the Adventurers need to unwind from their latest case. Which is how the team finds themselves at the Ragnarsson family estate along the Magdalena River in Colombia, even while team member Thyri conducts a little side business. Following the advice of a family member, Thyri is considering buying into a profitable, local industry: emerald mining. Except there's a hitch: a violent anti-government/revolutionary gang has been using the mine as a front to raise money for their cause and forcing the locals into free labor. Well, Thyri and the team won't stand for that and are determined to shut down the gang's operation. Except the bad guys have other plans. Big plans. There will be blood.