The Doomsday Key (Sigma Force No. 6)

At Princeton University, a famed geneticist dies inside a biohazard lab. In Rome, a Vatican archaeologist is found dead in St. Peter's Basilica. In Africa, a U.S. senator's son is slain outside a Red Cross camp. Three murder victims on three continents, linked by a pagan Druidic cross burned into their flesh. Commander Gray Pierce and Sigma Force have only days to solve an apocalyptic puzzle dating back centuries. Aided by two women from his past -- one his ex-lover, the other his new partner -- Gray must uncover a horrifying secret that threatens America and the world, even if it means sacrificing the life of one of the women at his side. The race is on -- from the Roman Coliseum to the icy peaks of Norway to the lost tombs of Celtic kings -- and the future hangs in the balance. For humankind's ultimate nightmare is locked within a talisman buried by a dead saint -- an ancient artifact known as . . . The Doomsday Key.