Archaeologist Katja Bennecke is in charge of an excavation site at the foot of a Mayan pyramid on the Mexican headland of Yucatán. By chance, she discovers the mask of Gonzalo Guerrero, a Spanish warrior described in legends who rose to become supreme general under the Majas: a sensational find! Her colleague Gerd, of all people, tries to steal the valuable piece. But she catches the thief, who is immediately arrested and dies shortly afterwards under mysterious circumstances in a Mexican prison. Katja's daughter Maren arrives unexpectedly - and is kidnapped in the street. They want to release Maren in exchange for the mask. But the precious find does not belong to Katja. To save her daughter, she has to become a thief herself...