Young English lawyer David Martinez is completely perplexed. His just deceased grandfather, it turns out, left a will in which he left his grandson a lot of money from where he had come from - two million dollars. But with one condition: David must go to Spain, to the Basque Country, and find a certain Juan Garovillo there so that he can explain the meaning of the symbols on the old map, which David received under the same will. Intrigued, Martinez travels to the Basque Country. If he had known what a terrible secret was hidden in these symbols and what dangers awaited him on the way to solving it, then, most likely, he would have stayed at home, not caring about the inheritance. But he has no other way: after all, David, like his entire family, is inextricably linked with this secret by an ancient curse, whose name is the Mark of Cain...